J-A08021-19

2020 PA Super 88

COMMONWEALTH OF PENNSYLVANIA, IN THE SUPERIOR COURT

OF PENNSYLVANIA

Appellee

v.

GREGORY SCOTT HOPKINS

Appellant No. 941 WDA 2018

Appeal from the PCRA Order Enterer June 21, 2018

In the Court of Common Pleas of Beaver County

Criminal Division at No: CP-04-CR-0000580-2012

BEFORE: PANELLA, P.J., STABILE, and McLAUGHLIN, JJ.

OPINION BY STABILE, J.: FILED APRIL 6, 2020

Appellant, Gregory Scott Hopkins, who is serving a sentence of eight to 

sixteen years’ imprisonment for third degree murder,1 appeals from an order 

denying his petition under the Post Conviction Relief Act (“PCRA”), 

42 Pa.C.S.A. §§ 9541-46. The victim, Janet Walsh, was strangled to death in 

her apartment on September 1, 1979. The police interviewed Appellant, who 

admitted having a casual sexual relationship with Walsh that summer but 

insisted he was not with Walsh at the time of her death. In 2012, Appellant 

was charged with Walsh’s murder following the discovery of his seminal DNA 

on several items recovered from the crime scene. The Commonwealth 

presented expert testimony from a forensic pathologist, Cyril Wecht, M.D., 

that the “topographical distribution” of Appellant’s semen at the crime scene 

____________________________________________

1 18 Pa.C.S.A. § 2502(c).
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demonstrated he was with Walsh at the time of her death. In this appeal, 

Appellant argues that his trial counsel was ineffective for failing to file a Frye2

motion to preclude Dr. Wecht’s testimony on the ground that the methodology 

underlying his opinion was not generally accepted in the field of forensic

pathology. We agree with Appellant. The record demonstrates that no 

scientific method exists for dating DNA deposits, and that Dr. Wecht’s 

methodology is not generally accepted in the forensic pathology field. We 

conclude trial counsel had no reasonable basis for failing to seek preclusion of 

Dr. Wecht’s testimony under Frye, and the admission of his testimony caused 

substantial prejudice to Appellant. Accordingly, we reverse and remand for a 

new trial.

I. Factual and Procedural History

On September 1, 1979, Walsh’s father discovered her body in the 

bedroom of her apartment in Monaca, Pennsylvania. When police first 

observed her body that day, Walsh was lying face down, covered with a sheet. 

She was wearing a short nightgown, and her hands were bound behind her 

back with a cloth bathrobe belt. A bandana was wrapped around her neck,

and there was a bathrobe at the foot of the bed. There was no sign of forced 

entry into the apartment, where she resided alone. She had recently 

separated from her husband, Scott Walsh, and was in the process of obtaining 

a divorce.

____________________________________________

2 See Frye v. United States, 293 F. 1013 (D.C. Cir. 1923), adopted in 

Pennsylvania in Commonwealth v. Topa, 369 A.2d 1277 (Pa. 1977).
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The pathologist who performed Walsh’s autopsy concluded that she died 

from ligature strangulation between 5:00 a.m. and 7:00 a.m. on September 

1, 1979. Neither the investigating officers nor the pathologist who performed 

the autopsy observed signs of recent sexual activity. They found no signs of 

semen or ejaculate on her body, on her nightgown, on the top sheet or the 

fitted sheet from the bed, on the tie that bound her hands, or on her ligature. 

A State Police criminalist conducted a close visual inspection and textile 

examination of the physical evidence, which included running his hands over

the fabric, the clothing and ligature, and concluded there was no trace 

evidence of any sexual activity. 

The police did not recover any foreign pubic hairs. Swab samples from 

Walsh’s mouth and vagina revealed no evidence that she was engaged in

sexual conduct. An inspection for material under her fingernails was also 

negative. The medical examiner concluded that Walsh had not been raped 

and was not having sexual intercourse at the time of her death. 

On the evening before her death, Walsh went out dancing at a nightclub 

with friends. The last individuals with Walsh were Margie Farinacci, a friend, 

and Robert McGrail, a drifter who met Walsh that night and danced with her.

McGrail accompanied Walsh and Farinacci to a restaurant at 2:30 a.m., where 

he remained until at least 3:30 a.m. McGrail’s checkbook was found in a

gutter in the vicinity of Walsh’s apartment shortly after her murder.

At the beginning of the investigation, the police spoke to Appellant about 

his relationship with Walsh. Like Walsh, he was going through a divorce that 
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summer. He admitted having casual sex with her several times in her 

apartment during the summer of 1979. They sometimes had sex more than 

once in an evening, and he sometimes ejaculated on her back. He stated that 

their last sexual encounter in the apartment occurred three to four weeks 

before her death. Appellant claimed he was not with Walsh on the morning 

of her death but instead he was at home several miles from her apartment, 

where he woke up around 5:30 a.m. with guests to prepare for a pig roast he 

was holding for employees in his construction business. 

For more than thirty years after Walsh’s death, there were no 

investigative leads. In 2010, using technology not available in 1979, the State 

Police found Appellant’s seminal DNA on the top sheet that covered Walsh’s

body, the bathrobe belt tied around her hands, and her nightgown. In 2012, 

based on this DNA evidence, the Commonwealth charged Appellant with 

Walsh’s murder and advanced the theory that Walsh died during a sexual 

encounter with Appellant. The trooper who testified at Appellant’s preliminary 

hearing admitted he could not say whether semen deposits occurred on 

September 1, 1979 or some earlier date. The trooper did not know whether 

the clothing items were washed between Appellant’s sexual encounter(s) with 

Walsh prior to September 1, 1979. Most of the DNA found on the evidence 

was too degraded to be tested. Appellant’s DNA did not match swabs taken 

from Walsh’s vagina and mouth on September 1, 1979, and no DNA was 

obtained from the bandana used to strangle Walsh. 
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The Commonwealth obtained an expert report from Dr. Wecht that

addressed (1) how Appellant’s semen was likely deposited, and (2) the 

probability that Appellant’s seminal fluid was deposited during sex with the

decedent earlier in the summer of 1979. Dr. Wecht wrote that the placement 

of Appellant’s seminal fluid on the back of Walsh’s nightgown, the cloth belt

tied around her wrists, and the bed sheet “place him on the bed on top of the 

decedent’s back at/around the time of her demise.” Report, at 4. Dr. Wecht 

continued, “[I]t is extremely unlikely that [Appellant’s] seminal fluid was 

deposited in those locations during the two or three previous sexual 

encounters [Appellant] admitted to have engaged in during the summer three

weeks to a month prior to the victim’s death.” Id. He further opined that 

“the location of the seminal fluid in both areas where the fluid was identified 

is further consistent with the decedent’s position when found.” Id.

Dr. Wecht opined that the victim died due to strangulation during sexual 

activity hours before the discovery of her body, and that “the DNA of 

[Appellant’s] seminal fluid would have been deposited around the time of her 

death based on the locations where it was identified.” Id. He stated that,

given the DNA analysis, there was no evidence a third person was present. 

“[T]he absence of any signs of struggle or forced entry into her apartment,”

he contended, “is a strong, logical argument that [] Walsh’s assailant was 

someone she knew, and who would have been allowed entry into her 

apartment.” Id.
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Counsel for Appellant filed a pre-trial motion seeking preclusion of Dr. 

Wecht’s expert testimony and report on two grounds. First, counsel wrote, 

“the proffered expert testimony does not distinctly relate to a science, skill, or

occupation beyond the knowledge or experience of the average layman and is 

submitted only to buttress the Commonwealth’s argument on its theory of the 

case.” Appellant’s Brief in Support of Motion to Preclude, 10/19/12, at 1-2. 

Second, counsel stated, Dr. Wecht failed to express his opinion with the 

requisite degree of certainty by stating the semen was “likely” deposited 

around the time of Walsh’s death, and it was unlikely the semen was deposited 

on previous occasions. Id. at 5-6 (citing Commonwealth v. Davido, 868 

A.2d 431, 441 (Pa. 2003) (“[t]he expert has to testify . . . that in his 

professional opinion the result in question came from the cause alleged. A 

less direct expression of opinion falls below the required standard of proof and 

does not constitute legally competent evidence”)). Counsel, however, did not

file a Frye motion to preclude the evidence on the ground that Dr. Wecht’s 

methodology of ascertaining the date of the DNA deposits from their locations

at the crime scene was not generally accepted in the forensic community. At 

oral argument on November 13, 2012, counsel repeated the arguments he 

made in the motion to preclude, N.T., 11/13/12, at 2-13, and criticized Dr. 

Wecht’s report as “conjecture and speculation,” id. at 3, 6, 9, but did not 

argue that Dr. Wecht’s testimony was inadmissible under Frye.

In an opinion and order dated November 5, 2012, the trial court granted 

Appellant’s motion to preclude, reasoning:
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[Dr. Wecht’s] report does not set forth any scientific manner upon 

which [he] bases his conclusion that [Appellant] was on top of the 

decedent’s back around the time of her demise. Further, the 

report does not set forth the scientific method or means by which 

Dr. Wecht reaches the conclusion that because the DNA was found 

only on the bed sheet, the rope tie, and the nightgown, it is 

unlikely that [Appellant]’s seminal fluid was placed there during 

sexual relations that occurred three weeks to a month earlier. As 

such, Dr. Wecht does not state a precise scientific basis for his 

conclusions, and Dr. Wecht’s assertions are not set forth or 

posited in a sufficiently specific manner. Furthermore, we 

conclude that Dr. Wecht’s statement that “it is extremely unlikely”

that the seminal fluid was placed in certain locations several weeks 

earlier, given the locations where the fluid was found, is too vague 

and imprecise to meet the standard for competent expert medical 

testimony in accordance with Pennsylvania law. Therefore, the 

opinions set forth in his report are speculative in nature and are 

thus not admissible. Moreover, we conclude that the question 

regarding whether it is unlikely that the seminal fluid was placed 

in the locations where the fluid was found at a time several weeks 

earlier does not necessitate the use of scientific, technical or 

specialized knowledge beyond that possessed by a layperson.

Trial Court Opinion, 11/5/12, at 6.

Pursuant to Pa.R.A.P. 311(d), the Commonwealth timely appealed to 

this Court at Docket No. 1776 WDA 2012 on the ground that the trial court’s 

order substantially handicapped the prosecution of this case. In this Court, 

counsel for Appellant3 made the same arguments that he made in the trial 

court, i.e., Dr. Wecht’s opinion was speculative, was not expressed with the 

requisite degree of certainty, and did not relate to a science, skill, or 

____________________________________________

3 Appellant was the appellee in the appeal at 1776 WDA 2012, but for the sake 

of consistency, we continue to refer to him as “Appellant.”
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occupation beyond the knowledge or experience of the average layperson. 

Brief for Appellant, 1776 WDA 2012, at 10-18.4 Counsel added that Dr. Wecht 

“[did] not . . . set forth any probative facts to support his conclusions that the 

seminal fluid was deposited on the day in question as opposed to some other 

date.” Id. at 12. 

In a 2-1 decision, this Court reversed and, without elaboration, held that 

Dr. Wecht’s report “[met] Pennsylvania’s liberal standard for expert 

testimony,” because he “assert[ed] facts not generally known but known to 

him because of his special training and experience.” Commonwealth v. 

Hopkins, 1776 WDA 2012, unpublished memorandum at 6-7 (Pa. Super. filed 

October 4, 2013)). The majority also held that Dr. Wecht stated his opinion 

“with the requisite degree of certainty.” Id. at 7. Judge Ford Elliott dissented

on the ground that 

Dr. Wecht’s conclusions appear to be merely his own thoughts on 

the evidence and not based on any scientific or forensic analysis. 

In addition, as the trial court states, the issue whether, as Dr. 

Wecht concluded, it was “extremely unlikely” [Appellant’s] 

seminal fluid could have been deposited three weeks earlier, 

based on the locations where the fluid was found, without more to 

substantiate this conclusion, does not represent the use of 

scientific or technical knowledge beyond that possessed by a 

layperson. 

____________________________________________

4 Appellant did not include this brief in his reproduced record in the present 

appeal, but we have the authority to take judicial notice of the entire record 

in this case, including all prior proceedings. In Re Schulz’ Estate, 139 A.2d 

560, 563 (Pa. 1958).
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Id., concurring and dissenting memorandum at 1-2. Appellant did not seek 

further review by our Supreme Court. 

The case proceeded to a jury trial. Trooper Matas, the state trooper 

who investigated the crime scene on September 1, 1979, testified that he saw 

the victim lying face down on her bed with a bandana tied around her neck 

and her hands bound behind her back. N.T. Trial, 11/13/13, at 25-26. To 

observe the victim in this position, he removed the top sheet that covered her

(the sheet on which investigators discovered Appellant’s DNA decades later).

Id. at 26. He also learned that (1) the victim’s body had been covered by a 

sheet when her father discovered her body earlier that morning, and (2) her 

father had “removed the sheet to a certain extent, and I can’t tell you to what 

extent.” Id. at 68. The trooper added that prior to his arrival, the sheet had 

been removed from the body, and “not just once.” Id.

The trooper acknowledged that as a trained investigator, he would have 

looked carefully at the nightgown on the victim’s body. Id. at 76. He did not 

notice any staining or wet marks on the nightgown. Id. at 76-77. Nor was 

the nightgown sticking to the victim’s back in any way. Id. at 77. He knew 

what semen looked like on material, but he did not observe any white or crusty 

material on the nightgown. Id. Nor did he see any stain or crust on the robe 

tie that bound the victim’s hands. Id. at 78.

Ashlee Mangan, a State Police forensic scientist, testified that she 

examined evidence from the crime scene in 2010. Using an alternate light 
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source, she identified two areas of sperm on the top right and middle portions

of the sheet, as well as areas of sperm on both the robe tie that bound the 

victim’s hands and her nightgown. N.T. Trial, 11/15/13, at 64, 107-08. None 

of these areas were visible to the naked eye. Id. at 114. She agreed that 

DNA testing does not determine when sperm is deposited. Id. at 92.

The Commonwealth called Dr. Wecht to the stand. Dr. Wecht testified 

that he has been recognized as an expert in forensic pathology in 

Pennsylvania, throughout the United States, and in other parts of the world. 

Id. at 155. He has participated in “countless” homicide cases, has authored 

570 publications relating to forensic pathology and related subjects, and has 

authored or edited 44 books for the professional field. Id. at 156-57. A school 

is named after him, the Cyril Wecht Institute of Forensic Science and Law at 

Duquesne University. Id. at 157. Based on these credentials, the trial court 

admitted Dr. Wecht to testify for the Commonwealth as an expert in forensic 

pathology. Id. at 158. 

Dr. Wecht testified that a forensic pathologist is a medical doctor who 

has trained five or six years in pathology following medical school. Id. Among 

other things, a forensic pathologist determines the cause of sudden, violent, 

unexpected deaths. Id. at 159-60. Dr. Wecht told the jury that the victim 

died from strangulation from behind during sexual intercourse, and he stated:

The reports indicated that seminal fluid matched the DNA to 

[Appellant] was found in three locations, what is referred to as the 

flat sheet, the sheet, I guess, beneath the blanket that overlies 

the body when you would be in bed normally and then on a, an 
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upper nightgown, like a nightgown top, and then the bathrobe belt 

that had encircled her hands[.]

Id. at 173. In Dr. Wecht’s opinion, the “topographical distribution” of 

Appellant’s semen, i.e., the three locations in which Appellant’s semen was 

found, showed that all of the semen was deposited at the same time, around 

the time of Walsh’s death. Id. at 173-74. Dr. Wecht rejected Appellant’s 

contention that transmission of semen took place during a sexual encounter 

three to four weeks before Walsh’s death, stating:

Number one, I believe, based upon these three locations, they’re 

topographical distribution. They adjunct the position and so on, 

and the position of the body was found face down, prone, that 

that was the result of an ejaculation, a male ejaculation that 

occurred as the victim was lying down and that some of the 

ejaculate got into her, in those locations. That’s number one.

Number two, the three areas that fit in also in terms of that 

anatomical topographical distribution. DNA testing does not 

tell you in and of itself the time that that material,

whatever it may have been, has been deposited. That is 

correct. That needs to be said as part of the answer.

My opinion is based upon the locations of the three sites at 

which the seminal material was found, the position of the body, 

and then when I consider that with the suggestion that these sites 

could have been the result of a deposition of male ejaculate three, 

four weeks before, I find that hard to believe. As a 23-year-old 

woman, she has a job. She works. She sees people. She has a 

social life and so on. For me from an investigative analytical

standpoint to conceive that somehow four weeks have gone by 

and she has not thoroughly washed a sheet that she sleeps under, 

that she has not washed the belt of a bathrobe that she uses, that 

she’s still wearing a nightgown that she sleeps in, I just find that 

extremely unlikely and [it] is on all of those findings that I express 

the opinion that I did.
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Id. at 173-75. (Emphasis added). Dr. Wecht also “[could not] accept” the 

premise that DNA was transferred in the process of washing garments:

If there was such contamination via washing, then it might have 

been here, might have been there. But I find it extremely unlikely, 

remarkably fortuitous that there would have been such 

contamination resulting in the deposition then of seminal material 

in those three places that you have contamination from the 

washing that Miss Walsh would have undertaken presumably by 

herself, out come the garments and so on, and lo[] and behold 

there are the seminal stains right there where she was found 

bound on that bathroom rope, on the nightgown, and on the sheet 

that overlies it in that area.

I just . . . can’t accept that kind of explanation, so the process of 

contamination in general, theoretically, can it occur, yes. Does it 

occur then in those three topographical areas that fit perfectly into 

this sexual assault homicide, no, I don’t believe that that is at all 

likely.

Id. at 181. Dr. Wecht emphasized that ”all of the opinions I have expressed 

have been expressed within a reasonable degree of medical forensic scientific 

certainty of probability.” Id. at 183; see also id. at 220 (all of his opinions 

were within a reasonable degree of “forensic pathological and forensic 

scientific certainty”).

Dr. Wecht admitted he could not date the deposit of DNA based upon 

the locations where it was identified. Indeed, he admitted that no test 

existed for dating DNA deposits, id. at 214, an admission with which every 

other witness who gave expert testimony on DNA findings concurred. Id. at 

144-45 (State Police forensic scientist Biondi); N.T. Trial, 11/15/13, at 92 

(Mangan); N.T. Trial, 11/18/13, at 32-33, 40 (State Police forensic DNA 

scientist Brown); N.T. Trial, 11/20/13, at 80 (defense DNA expert Perlin). Dr. 
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Wecht could not explain how Appellant could have ejaculated on Walsh without 

detection of his semen by police, crime lab analysts, and medical personnel 

who observed Walsh’s body and linens within a few hours of her death. Id. 

at 185, 193-94, 198-99. He further admitted that because DNA transfers from 

one object to another, it is impossible to state that the place upon which DNA 

is presently located is the exact location upon which the contributor deposited 

it in the first place. Id. at 180-81.

Counsel for Appellant did not ask Dr. Wecht whether the methodology 

he used was generally accepted in the scientific community. Nor did the 

Commonwealth show, or attempt to show, that the science of forensic 

pathology generally accepts a methodology to date DNA deposits based on 

“topological distribution.”

Appellant called two experts, Dr. Mark Perlin, a DNA expert, and Dr. 

Michael Panella,

5 a forensic pathologist. Both experts disagreed with Dr. 

Wecht’s conclusions that the location of the sperm and position of the victim’s 

body showed that Appellant deposited the sperm around the time of the 

victim’s death. Dr. Panella, for example, opined that there could be other 

reasons why the semen was in these particular locations, including (1) semen 

could have been deposited during sexual encounters prior to the night of the 

victim’s death, (2) semen could have been transferred to these locations at 

____________________________________________

5 President Judge Panella does not know nor is he related to Dr. Michael 

Panella.
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other times from other bedding, and (3) “there is also a possibility that when 

articles have, are washed . . . the semen, the sperm can actually lift off the 

contaminated garments that are being washed and deposit on the other pieces 

of the garments that have not been stained and then, now they are 

contaminated with sperm.” N.T. Trial, 11/19/13, at 38-39. Counsel for 

Appellant did not ask either expert, however, whether Dr. Wecht’s 

methodology was generally accepted in the scientific community. 

During closing arguments, the Commonwealth relied heavily on Dr. 

Wecht’s testimony:

Now, you heard a lot from experts, and our expert, of course, was 

Dr. Wecht, who you heard testify, who told you, in his opinion—

this wasn’t just coming out of nowhere, as has been suggested. 

His opinions were based on his experience, and it was based upon 

a reasonable degree of forensic pathological certainty. He applied 

his 52 years of experience to this case. Dr. Wecht has seen it all, 

340 autopsies this year alone, a medical practice going back 52 

years.

N.T. Trial, 11/21/13, at 87. The Commonwealth continued:

Use your common sense, because when [Dr. Wecht] says that 

[Appellant is] on top of Janet Walsh when he kills her, that is 

evident, and then stop right there. What does that do? Right in 

her mid back is a spot where [Appellant’s] seminal fluid is found, 

and . . . when you have that the rope around her hands is right 

here, the knot on the ligature is going to be right there, right there 

(indicating), and it all lines up. It all lines up to the person who 

Dr. Wecht says was right on top of her and ejaculates on her back 

while holding that ligature. Dr. Wecht also told us that to believe 

that the last time [Appellant] was at her house was three or four 

weeks before, and the way that she’s found, and where the 

seminal fluid is, and knowing that, how he knew she was, that you 

would have to believe . . . that someone else somehow came into 

her apartment, killed her, left her with seminal fluid in those exact 

locations, tied her up like that, and left and wasn’t found, nothing 
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but truth. You see what I’m saying? She is found that way, and 

to believe that someone else came in there, left her in that position 

in the exact area where the seminal fluid is, and no one else left 

a trace, no other person, no other person on the gown or on that 

ligature, so you would have to believe that someone else came 

there and then left her the way she was, naked from the waist 

down, and that’s how she was, and that somehow, after three or 

four weeks had passed, she’s in that exact same position with 

somebody else, that, ladies and gentlemen, is impossible. It’s 

hard to believe that that seminal fluid somehow was cross 

contaminated onto the robe, the gown, and the sheet, and then 

found as we saw. That is absurd. Just like Dr. Wecht said, we 

would have to believe in an absurdity. That seminal fluid was

deposited at the time of her death. That seminal fluid was left on 

her exactly in that spot on that robe as he straddled over her at 

the time he strangled her, because we know that she was being 

strangled from behind because of the ligature marks, the ligature. 

That seminal fluid was deposited at the marks on her neck and 

where that knot is, is where that fluid is, and [Appellant] cannot 

be excluded from it.

Id. at 95-97. “Science,” the Commonwealth argued, “caught up to 

[Appellant].” Id. at 98. 

On November 22, 2013, the jury found Appellant guilty of third-degree 

murder. On February 26, 2014, the trial court sentenced Appellant to eight 

to sixteen years’ imprisonment with credit for time served from January 29, 

2012 until December 4, 2012 and from November 22, 2013 until the date of 

sentence. Appellant filed timely post-sentence motions, which the trial court 

denied, and a timely direct appeal. The trial court issued an opinion rejecting 

Appellant’s challenge to the sufficiency of the evidence:

It was . . . determined by Crime Lab [that] the semen found on 

the nightgown top, robe tie around the victim’s wrists, and flat 

sheet covering the victim matched [Appellant’s] DNA. . . . 

Furthermore, the only semen found on the nightgown top and 

robe tie matched [Appellant]. Given the location of the semen on 
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the bedsheet that covered most of the victim’s body, and the fact 

that [Appellant’s] semen was also found on the nightgown and the 

robe tie binding her hands behind her back, the Commonwealth 

proved beyond a reasonable doubt that [Appellant] was the 

perpetrator and killed the victim with malice.

Trial Court Opinion, 8/26/14, at 70.

On direct appeal, Appellant challenged the sufficiency and weight of the 

evidence and argued that the trial court erred by refusing to sustain his Fourth 

Amendment objection to the seizure of his discarded drinking cup. On August 

31, 2015, a panel of this Court affirmed his judgment of sentence. See

Commonwealth v. Hopkins, 964 WDA 2014, unpublished memorandum at 

5 (Pa. Super. filed August 31, 2015). On July 22, 2016, the Supreme Court 

denied Appellant’s petition for allowance of appeal.

On June 21, 2017, Appellant filed a timely PCRA petition alleging, inter 

alia, that trial counsel was ineffective for failing to request exclusion of Dr. 

Wecht’s “topographical distribution” opinion under Frye on the ground that 

his methodology was not generally accepted in the scientific community. On 

December 5, 2017, the PCRA court convened an evidentiary hearing on 

Appellant’s petition. Appellant presented the testimony of Dr. David Fowler, 

the chairperson and former President of the National Association of Medical 

Examiners, and Dr. Kimberly Collins, the incoming President of the National 

Association of Medical Examiners. The court found both witnesses qualified 

as experts in forensic pathology.
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Counsel asked Dr. Fowler whether the science of forensic pathology 

generally accepts “topographical distribution” as a methodology from which 

Dr. Wecht could date a deposit of Appellant’s DNA. N.T. PCRA Hearing, 

12/5/17, at 14. Dr. Fowler answered, “No, that’s not medical science.” Id. 

When asked whether he ever heard of a forensic pathologist attempting to 

date a DNA deposit based on topographical distribution, Dr. Fowler answered,

“No, this would be a first for me.” Id. Dr. Fowler confirmed that there are no 

standards, no studies, no tests, and no generally accepted methodology in the 

field of forensic science to determine the date of a seminal DNA deposit. Id. 

at 15. He concluded that Dr. Wecht’s opinion was not rooted in the science of 

forensic pathology, and that no forensic pathologist is capable of opining the 

date of deposit of seminal DNA. Id. at 16; see also id. at 23 (topographical 

distribution is “not something that forensic pathologists typically do. It’s 

outside the national practice standards”). 

Similarly, PCRA counsel asked Dr. Collins “[whether] the science of 

forensic pathology properly allow[s] for the types of conclusions that Dr. 

Wecht rendered in this case.” Dr. Collins answered, “None whatsoever, not 

only pathology, but not scientifically.” Id. at 34. Dr. Collins confirmed that 

“not only is [topographical distribution] not a methodology, I’ve never even 

heard or used that terminology in forensic pathology.” Id. at 35. When asked 

if there is any methodology for the dating of a DNA deposit, she answered,

“[N]one whatsoever.” Id. When asked if she ever heard of dating based upon 
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the topographical distribution of samples, she said that she has never heard 

of it “because it is impossible.” Id. Nor had she heard of a single study that 

has evaluated whether “topographical distribution” is a valid scientific method 

for dating the deposit of DNA. Id. at 35-36. When asked whether there is a 

generally accepted methodology in the field of forensic science, or in any field 

of science, from which to draw Dr. Wecht’s opinions, she answered, “[N]o.” 

Id. at 36. When PCRA counsel asked if Dr. Wecht’s testimony was outside 

the bounds of proper forensic pathology, she stated, “[M]ost definitely.” Id.

Trial counsel for Appellant was the next witness. He admitted that Dr. 

Wecht’s testimony was “one of the pivotal issues” in the case and 

acknowledged filing a motion to preclude Dr. Wecht’s testimony. Id. at 52. 

He admitted, however, that he did not seek preclusion under Frye on the 

ground that Dr. Wecht’s methodology was not generally accepted in the 

relevant field. Specifically, trial counsel testified, “I didn’t argue that specific 

point, but I did argue that it wasn’t science. . . . I stated that it did not relate 

to a science, skill or occupation beyond the knowledge or experience of the 

average layman[.]” Id. at 53-54. Nor did trial counsel recall investigating 

whether “topographical distribution” was a generally accepted method used in 

the field of forensic pathology to date a DNA sample. Id. at 58 (trial counsel’s 

admission that he did not recall discussing this subject with Dr. Panella). 

Trial counsel contended that he thought he was “on such solid footing”

on the issues he raised that he “didn’t consider anything else.” Id. at 60. 
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PCRA counsel inquired, “But if you would have known that topographical

distribution was an invalid methodology to date DNA samples and that Dr. 

Wecht was testifying outside the realm of forensic science when he rendered 

those opinions, you would have raised that as an issue, is that correct[?]” Id. 

at 60-61. Trial counsel answered, “I can’t tell you that for sure from this 

standpoint. I could have raised it in the alternative if I had known at that 

point in time what you’re saying to be true. I don’t know whether it’s true or 

not.” Id. at 61. PCRA counsel asked, “And you just didn’t know anything 

more about topographical distribution sufficient to raise it at that point?” Id. 

at 62. Trial counsel answered, “It wasn’t something that we explored, no.” 

Id.

Dr. Wecht did not testify at the PCRA hearing. The Commonwealth did 

not present any expert testimony in response to Drs. Fowler and Collins.

On June 7, 2018, the court denied PCRA relief on the ground that Dr. 

Wecht’s opinion was not subject to Frye because it was not “scientific”

testimony. The trial court held “[Dr. Wecht’s opinion] regarding the use of 

scientific evidence to adduce the time and intentional nature of the incident, 

which is unsupported by scientific methods or theory, is not subject to a Frye

analysis as such testimony is not scientific testimony but merely opinion 

testimony that is improper for an expert to provide when testifying as an 

expert.” PCRA Court Opinion, 6/7/18 at 7. Appellant filed a timely notice of 

appeal, and both Appellant and the court complied with Pa.R.A.P. 1925. 
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In this Court, Appellant raises three issues:

1. Whether trial counsel was ineffective for failing to request the 

Court conduct a Frye hearing, to investigate and call available 

expert witnesses at such a hearing and to object based on Rule 

702(c) of the Pennsylvania Rules of Evidence to the testimony of 

Dr. Cyril Wecht, that based on “topographical distribution,” he 

could render an expert, scientific opinion that [Appellant’s] DNA 

was placed on the victim’s clothing and bed sheet the morning of 

her homicide?

2. Whether trial counsel was ineffective for failing to properly 

examine witnesses and to explain to the jury the factual 

insignificance of the “4+” rating assigned by the Pennsylvania 

State Police Crime Lab to [Appellant’s] seminal deposits?

3. Whether the Trial Court erred in refusing to order the 

Commonwealth to produce the microscopic slides, the identity of 

the stain used to mark the slides and the protocol used to derive 

the “4+” rating for examination by [Appellant’s] expert in 

conjunction with her PCRA hearing testimony?

Appellant’s Brief at 4. We find Appellant’s first issue that trial counsel was 

ineffective for failing to seek preclusion of Dr. Wecht’s testimony under Frye

entitles him to PCRA relief, and therefore we find no need to address any 

remaining issues.

II. Frye and Expert Testimony under Pennsylvania Rule of Evidence 

702.

In 1977, our Supreme Court adopted Frye in Topa, supra, and it has 

remained in force since that time. Under Frye, “novel scientific evidence is 

admissible if the methodology underlying the evidence has general acceptance 

in the relevant scientific community.” Grady v. Frito-Lay, Inc., 839 A.2d 

1038, 1043-44 (Pa. 2003). The requirement of general acceptance in the 

scientific community 
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assures that those most qualified to assess the general validity of 

a scientific method will have the determinative voice. Additionally, 

the Frye test protects prosecution and defense alike by assuring 

that a minimal reserve of experts exists who can critically examine 

the validity of a scientific determination in a particular case. Since 

scientific proof may in some instances assume a posture of mystic 

infallibility in the eyes of a jury of laymen, the ability to produce 

rebuttal experts, equally conversant with the mechanics and 

methods of a particular technique, may prove to be essential.

Topa, 369 A.2d at 1282. 

When first adopted in 1998, the Pennsylvania Rules of Evidence did not 

expressly incorporate Frye. As initially adopted, Pa.R.E. 702, the rule 

governing the admission of expert testimony, provided: 

If scientific, technical or other specialized knowledge beyond that 

possessed by a layperson will assist the trier of fact to understand 

the evidence or to determine a fact in issue, a witness qualified as 

an expert by knowledge, skill, experience, training or education 

may testify thereto in the form of an opinion or otherwise.

Pa.R.E. 702 (1998 version). Although Rule 702 as originally adopted was 

silent with regard to Frye, the comment to that rule explained that Frye 

continued to remain in force. See Pa.R.E. 702, Explanatory Comment—1998 

(“[a]doption of Pa.R.E. 702 did not alter Pennsylvania’s adoption of the 

standard in [Frye], which requires scientific evidence to have ‘general 

acceptance’ in the relevant scientific community”).

In 2003, the Pennsylvania Supreme Court granted review in Grady to 

consider whether to replace Frye with the standard adopted in federal courts 
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in Daubert v. Merrell Dow Pharmaceuticals, Inc., 509 U.S. 579 (1993).6 

The Grady court opted to retain Frye and reject Daubert, reasoning:

Frye’s “general acceptance” test is a proven and workable rule, 

which when faithfully followed, fairly serves its purpose of 

assisting the courts in determining when scientific evidence is 

reliable and should be admitted.

One of the primary reasons we embraced the Frye test in Topa

was its assurance that judges would be guided by scientists when 

assessing the reliability of a scientific method. See Topa, 369 

A.2d at 1281 (quoting United States v. Addison, 498 F.2d 741, 

744 (D.C.Cir.1974)). Given the ever-increasing complexity of 

scientific advances, this assurance is at least as compelling today 

as it was in 1977, when we decided that case. We believe now, 

as we did then, that requiring judges to pay deference to the 

conclusions of those who are in the best position to evaluate the 

merits of scientific theory and technique when ruling on the 

admissibility of scientific proof, as the Frye rule requires, is the 

better way of insuring that only reliable expert scientific evidence 

is admitted at trial.

Grady, 839 A.2d at 1045. 

Effective March 18, 2013, eight months before Appellant’s trial, the 

Court amended Rule 702 to provide as follows: 

A witness who is qualified as an expert by knowledge, skill, 

experience, training, or education may testify in the form of an 

opinion or otherwise if:

(a) the expert’s scientific, technical, or other specialized 

knowledge is beyond that possessed by the average layperson;

____________________________________________

6 Daubert abandoned Frye’s “general acceptance” requirement in favor of a 

test under which the trial judge evaluates whether the evidence will assist the 

trier of fact, and whether the evidence is reliable and scientifically valid. Id., 

509 U.S. at 592. 
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(b) the expert’s scientific, technical, or other specialized 

knowledge will help the trier of fact to understand the evidence or 

to determine a fact in issue; and

(c) the expert’s methodology is generally accepted in the 

relevant field.

Id. (emphasis added). Through the addition of subsection (c), the Court 

expressly incorporated Frye into Rule 702.7 Amended Rule 702 remains in 

effect today. 

The inclusion of “and” at the end of Rule 702(b) demonstrates that the 

proponent of expert testimony must satisfy all three subsections of the rule, 

including subsection (c), in order for expert opinion testimony to be 

admissible. Commonwealth v. Walker, 92 A.3d 766, 789 (Pa. 2014) (“to 

be admissible under Rule 702, evidence must not only be beyond the 

knowledge possessed by [a] layperson, and assist the trier of fact to 

understand the evidence, but it also . . . must pass the Frye ‘general 

acceptance’ test”). Appellant’s current appeal asserts that trial counsel was 

ineffective for failure to object to the testimony of Dr. Wecht on the basis that 

the methodology ostensibly relied upon by Dr. Wecht, “topographical

distribution,” failed to meet the requirements of Rule 702(c).

____________________________________________

7 For purposes of this opinion, since Rule 702(c) embodies Frye, we refer to 

both “Rule 702(c)” and Frye interchangeably and treat them as synonymous.
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III. Not Previously Litigated or Waived

Before examining the merits of Appellant’s Frye argument, we consider 

whether it is barred as previously litigated or waived. PCRA petitioners must 

plead and prove that an allegation of error has not been previously litigated. 

42 Pa.C.S.A. § 9543(a)(3). An issue has been “previously litigated” when 

either “the highest appellate court in which the petitioner could have had 

review as a matter of right has ruled on the merits of the issue,” 42 Pa.C.S.A. 

§ 9544(a)(2), or “it has been raised and decided in a proceeding collaterally 

attacking the conviction or sentence.” 42 Pa.C.S.A. § 9544(a)(3). 

Additionally, an issue is waived “if the petitioner could have raised it but failed 

to do so before trial, at trial, during unitary review, on appeal or in a prior 

state postconviction proceeding.” 42 Pa.C.S.A. § 9544(b).

Appellant’s Frye issue was not previously litigated under Section 

9544(a)(3), because there have been no prior collateral proceedings in this 

case, and defense counsel did not raise Frye during pretrial or trial 

proceedings. 

Nor was this issue previously litigated under Section 9544(a)(2). This 

subsection focuses not on what the PCRA petitioner raised or could have 

raised, but on whether the “highest appellate court in which the petitioner 

could have had review as a matter of right” ruled on the merits of the issue in 

question. In non-capital cases such as this, the Superior Court is the highest 

appellate court in which Appellant could have had review as a matter of right. 
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See 42 Pa.C.S.A. § 722 (defining classes of cases in which parties have right 

of direct appeal to Supreme Court), and § 742 (“[t]he Superior Court shall 

have exclusive appellate jurisdiction of all appeals from final orders of the 

courts of common pleas . . . except such classes of appeals as are by any 

provision of this chapter within the exclusive jurisdiction of the Supreme Court 

or the Commonwealth Court”). In the Commonwealth’s pretrial appeal at 

1776 WDA 2012, it argued only that the trial court erred by excluding Dr. 

Wecht’s testimony under Pa.R.E. 702(a) and (b). It did not argue that Dr. 

Wecht’s methodology satisfied Frye. In reversing the trial court, we held that 

Dr. Wecht “assert[ed] facts not generally known but known to him because of 

his special training and experience” and that he stated his opinion “with the 

requisite degree of certainty,” Hopkins, 1776 WDA 2012, at 6-7. We did not, 

however, address whether his methodology was generally accepted in the field 

of forensic pathology, a requirement under Pennsylvania law since Topa’s 

issuance in 1977. We likewise did not address Frye in Appellant’s direct 

appeal following his conviction. We simply rejected Appellant’s challenges to

the sufficiency and weight of the evidence and his Fourth Amendment 

argument concerning the seizure of his drinking cup. 

Lastly, Appellant has not waived his Frye argument, because he raised 

it in a timely PCRA petition alleging ineffective assistance of counsel. 

Commonwealth v. Grant, 813 A.2d 726, 738 (Pa. 2002) (in general, 

petitioners must wait to raise claims of ineffective assistance of trial counsel 
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until collateral review; ineffectiveness claims are waived only after petitioner 

has had the opportunity to raise that claim on collateral review and has failed 

to avail himself of that opportunity).

Accordingly, we proceed to the merits of Appellant’s Frye argument.

IV. Ineffective Assistance Standards

To obtain relief on a claim of ineffective assistance of counsel, Appellant 

must prove that: (1) the underlying claim has arguable merit; (2) counsel 

lacked a reasonable basis for his actions or failure to act; and (3) the petitioner 

was prejudiced by counsel’s deficient performance such that there is a 

reasonable probability that the result of the proceeding would have been 

different absent counsel’s error or omission. Commonwealth v. Pierce, 527 

A.2d 973, 975 (Pa. 1987). Counsel is presumed to have rendered effective 

assistance. Commonwealth v. Sepulveda, 55 A.3d 1108, 1117 (Pa. 2012).

When reviewing a PCRA order, we examine whether the record supports 

the PCRA court’s factual findings and whether its legal conclusions are free 

from error. Commonwealth v. Hannibal, 156 A.3d 197, 206 (Pa. 2016). 

We view the PCRA court’s findings and evidence of record in the light most 

favorable to the prevailing party. Commonwealth v. Koehler, 36 A.3d 121, 

131 (Pa. 2012). The PCRA court’s credibility determinations, when supported 

by the record, are binding, but we review the PCRA court’s legal conclusions

de novo. Commonwealth v. Roney, 79 A.3d 595, 603 (Pa. 2013). The 

petitioner has the burden of persuading us that the PCRA court erred and that 
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such error requires relief. Commonwealth v. Wholaver, 177 A.3d 136, 144-

45 (Pa. 2018).

a) Arguable Merit

Appellant argues that trial counsel was ineffective for failing to raise a 

Frye objection to Dr. Wecht’s testimony. We hold that this claim has merit 

because Dr. Wecht’s methodology, “topographical distribution,” was “novel” 

science not generally accepted in the field of forensic pathology.

“Frye, by definition, only applies where expert testimony is required.” 

Trach v. Fellin, 817 A.2d 1102, 1108 (Pa. Super. 2003) (en banc). Frye

precludes expert testimony when the expert’s methodology (1) is “novel 

science” and (2) is not generally accepted in the relevant field. Id. at 1110. 

“[S]ince Frye is an exclusionary rule of evidence, it must be construed 

narrowly so as not to impede admissibility of evidence that will aid the trier of 

fact in the search for truth.” Walsh v. BASF Corporation, 191 A.3d 838, 

848 (Pa. Super. 2018). Frye does not examine whether the expert’s 

conclusions are valid, but simply evaluates whether he used valid methods to 

reach his conclusions. Trach, 817 A.2d at 1112. 

“Scientific” methodology is based on

generating hypotheses and testing them to see if they can be 

falsified; indeed, this methodology is what distinguishes science 

from other fields of human inquiry. . . . Stated differently, the 

scientific method is a method of research in which a problem is 

identified, relevant data are gathered, a hypothesis is formulated 

from these data, and the hypothesis is empirically tested. Within 

the meaning of the definition of the scientific method, empirical 

means provable or verifiable by experience or experiment. Key 
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aspects of the scientific method include the ability to test or verify 

a scientific experiment by a parallel experiment or other standard 

of comparison (control) and to replicate the experiment to expose 

or reduce error.

Id. at 1113 (citations and quotations omitted). 

“Novel” scientific evidence

is usually decided on a case-by-case basis as there is some 

flexibility in the construction, as science deemed novel at the 

outset may lose its novelty and become generally accepted in the 

scientific community at a later date, or the strength of the 

proponent’s proffer may affect the Frye determination. . . . Just 

when a scientific principle or discovery crosses the line between 

the experimental and demonstrable stages is difficult to define. 

Somewhere in this twilight zone the evidential force of the 

principle must be recognized, and while courts will go a long way 

in admitting expert testimony deduced from a well-recognized 

scientific principle or discovery, the thing from which the 

deduction is made must be sufficiently established to have gained 

general acceptance in the particular field in which it belongs.

Walker, 92 A.3d at 790 (citations and quotations omitted). 

When an expert presents novel scientific evidence, Frye requires 

analysis of whether the methodology underlying the expert’s opinion is 

generally accepted in the relevant scientific community. “General acceptance” 

does not require universal acceptance of a given methodology. 

Commonwealth v. Blasioli, 713 A.2d 1117, 1126-27 (Pa. 1998). Courts 

accept a variety of sources as evidence that the expert’s methodology is 

generally accepted, including judicial opinions, Walker, 92 A.3d at 782-84; 

Commonwealth v. Nevels, 203 A.3d 229, 238-39 (Pa. Super. 2019), 

scientific publications, studies, and statistics, Blasioli, 713 A.2d at 1126-27, 

expert testimony, id., or a combination of the above. An expert need not rely 
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on studies that mirror the exact facts under consideration. Walsh, 191 A.3d 

at 848. It is sufficient if the synthesis of various legitimate studies reasonably 

permits the conclusion reached by the expert. Id. The absence of a treatise 

or study directly on point goes to the weight, not the admissibility, of the 

opinion. Id. Conversely, an expert’s personal belief, standing alone, is not

sufficient proof that his methodology is generally accepted. In Snizavich v. 

Rohm & Haas Company, 83 A.3d 191 (Pa. Super. 2013), we stated:

The exercise of scientific expertise requires inclusion of scientific 

authority and application of the authority to the specific facts at 

hand. Thus, the minimal threshold that expert testimony must 

meet to qualify as an expert opinion rather than merely an opinion 

expressed by an expert, is this: the proffered expert testimony 

must point to, rely on or cite some scientific authority—whether 

facts, empirical studies, or the expert’s own research—that the 

expert has applied to the facts at hand and which supports the 

expert’s ultimate conclusion. When an expert opinion fails to 

include such authority, the trial court has no choice but to 

conclude that the expert opinion reflects nothing more than 

mere personal belief[.]

Id. at 197 (citation omitted) (emphasis added). 

The PCRA court rejected Appellant’s Frye argument by declaring that 

Frye applies only to novel “scientific” methodology, whereas Dr. Wecht’s 

methodology was non-scientific, that is, it rested on “unscientific conjecture 

and speculation” that “every layperson uses.” PCRA Court Opinion, 6/7/18, 

at 20-21. During the PCRA hearing, one of Appellant’s experts, Dr. Fowler, 

testified that Dr. Wecht’s opinion was “not medical science.” N.T. PCRA 

Hearing, 12/5/17, at 14. Seizing upon these words, the PCRA court wrote:
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Had Dr. Wecht proposed to utilize some new method or technique 

to determine the date of the seminal DNA deposit . . . such novel 

methods would have been a prime instance of the necessity for a 

Frye hearing to determine the efficacy and general acceptance of 

this novel scientific methodology. In this case, however, such a 

novel method was not employed by Dr. Wecht. Rather, Dr. Wecht 

utilized accepted methods of DNA analysis to establish the 

presence of [Appellant’s] DNA at the scene, and then engaged in 

unscientific conjecture and speculation based on the locations of 

the DNA to opine to the likely time that the DNA was deposited. 

In other words, Dr. Wecht’s methodology, if one could call it that, 

was not scientific methodology: he employed no tests nor were 

measurements taken, only physical observation and speculation. 

If this can be described as a methodology, it cannot be described 

as scientific methodology, but rather the methodology every 

layperson uses when engaging in speculation, which is to say—as 

was said by trial counsel, his experts, and even PCRA counsel and 

his experts—it is not science at all.

PCRA Court Opinion, 6/7/18, at 20-21. As it did in its pretrial opinion, the 

court signaled its doubt about the quality of Dr. Wecht’s opinion. Despite its 

skepticism, the court concluded that Rule 702(c) applies only when an expert 

presents a “scientific” opinion based on methodology that is not generally 

accepted in the relevant field. Since Dr. Wecht’s opinion was non-scientific, 

the court said, Rule 702(c) did not apply, and he was free to base his opinion 

on speculation instead of generally accepted methodology.

The record is clear that Dr. Wecht failed to use scientific methodology

but instead resorted to offering his opinions based upon what he surmised 

from the physical evidence. Nevertheless, Rule 702(c) applied to his 

testimony because he purported to present a novel scientific opinion to the 

jury. 
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There was no generally accepted methodology underlying Dr. Wecht’s 

“topographical distribution” testimony. Dr. Wecht failed to cite any tests or 

studies demonstrating that “topographical distribution” is a valid forensic tool 

for identifying the time DNA is deposited. In fact, he admitted that he could 

not date the deposit of DNA based upon locations where it was identified, and 

acknowledged that no test exists for dating DNA deposits. During the PCRA 

hearing, Drs. Fowler and Collins gave unrebutted testimony that 

“topographical distribution” is not generally accepted in the field of forensic 

pathology. They stated unequivocally that there are no standards, studies, 

tests or generally accepted methodology in the field of forensic science to 

determine the date of a seminal DNA deposit. The Commonwealth did not 

present any testimony to rebut this testimony, or cite to any judicial decision 

that accepts “topographical distribution” as a valid method for identifying the 

time of DNA deposits. Nor have we found any such decision ourselves. The 

term “topographical distribution” is an impressive sounding label, but there is 

simply no methodology to support it. 

Dr. Wecht also failed to provide any generally accepted methodology in 

support of his contention that Appellant did not deposit any of the seminal 

fluid during intercourse with Walsh three to four weeks before her death. Dr. 

Wecht merely suggested that as a 23-year-old who worked and had a social 

life, the victim would have washed these items during the last month of her 

life. There was no evidence about the victim’s social life except that she was 
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in the process of divorcing her husband, had a casual sexual relationship with 

Appellant, and went out dancing with friends the night before her death. Nor 

was there any evidence about when she last washed her clothes or sheets 

before her death. There were no standards, empirical data or studies 

undergirding Dr. Wecht’s statement. It was simply his own personal opinion 

based upon his review of the physical evidence.

The question becomes whether Dr. Wecht’s opinion fell outside of Rule 

702(c)’s purview because it was “non-scientific.” We think not. Dr. Wecht 

presented a novel opinion to the jury that purported to be scientific. Since 

he portrayed his opinion as scientific, Rule 702(c) required him to support his 

opinion with generally accepted methodology. He failed to do so. 

The Commonwealth’s central theme during trial was that it solved a cold 

case, and brought a killer to justice, through science. To promote this thesis, 

Dr. Wecht, a renowned expert in forensic pathology, presented a novel 

topographical distribution theory—an opinion so novel that neither of 

Appellant’s experts ever heard of it—and stated repeatedly that it was within 

a reasonable degree of “scientific” certainty. N.T. Trial, 11/13/13, at 183, 

220. During closing arguments, the Commonwealth emphasized that “our 

expert,” Dr. Wecht, who has “seen it all” during his 52 years of medical 

practice, established to “a reasonable degree of forensic pathological 

certainty” that Appellant deposited the seminal fluid on the night of Walsh’s 

death. N.T. Trial, 11//21/13, at 87. “Science,” the Commonwealth concluded, 
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“caught up to [Appellant].” Id. at 98. In our view, the requirement that novel 

scientific opinions rest upon generally accepted methodology extends to novel 

opinions that purport to be scientific. Otherwise, juries will be exposed to 

opinions that masquerade as science but which rest on nothing more than 

personal belief—the very type of methodology that we cautioned against in 

Snizavich. Id., 83 A.3d at 197. Therefore, Rule 702(c) required Dr. Wecht

to back up his novel, and purportedly scientific, opinion with methodology 

generally accepted in the field of forensic pathology. 

Implicit in Dr. Wecht’s testimony is the suggestion that common sense 

is a valid substitute for scientific methodology, and as a matter of common 

sense, the three areas of sperm at the crime scene must have been deposited 

at the same time. Frye, however, requires experts to support their opinions 

with generally accepted methodology, not simply with common sense. If 

common sense alone were permissible, no need would exist for expert 

testimony; a lay witness could testify instead. Of equal importance, common 

sense is insufficient in this case, because it does not rule out the possibility 

that the deposits could have occurred during one or more prior sexual 

encounters in the summer of 1979. Nor does scientific methodology rule out 

this possibility, because as discussed above, scientific methodology provides 

no help at all in determining whether the deposits took place on the night of 

Walsh’s death or on some earlier date(s).
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We conclude that Dr. Wecht’s opinion testimony does not satisfy Frye

because it is not supported by any generally accepted methodology. Instead, 

we find the opinion testimony admitted is the type of opinion Frye is intended 

to preclude. The PCRA court confirmed the deficiencies in Dr. Wecht’s 

methodology by stating, “If this can be described as a methodology, it [was]

the methodology every layperson uses when engaging in speculation.” PCRA 

Court Opinion, 6/7/18, at 21. Accordingly, Appellant’s claim that trial counsel 

was ineffective for failing to raise a Frye objection to Dr. Wecht’s testimony 

has arguable merit.

b) Reasonable Basis for Counsel’s Inaction

“With regard to reasonable basis, the PCRA court does not question 

whether there were other more logical courses of action which counsel could 

have pursued; rather, [the court] must examine whether counsel’s decisions 

had any reasonable basis.” Commonwealth v. Mason, 130 A.3d 601, 618 

(Pa. 2015) (citation and punctuation omitted). “Where matters of strategy 

and tactics are concerned, [a] finding that a chosen strategy lacked a 

reasonable basis is not warranted unless it can be concluded that an 

alternative not chosen offered a potential for success substantially greater 

than the course actually pursued.” Id. (citations and punctuation omitted). 

Counsel’s decision to refrain from a particular action does not constitute 

ineffectiveness if it arises from a reasonable conclusion that there will be no 

benefit and is not “the result of sloth or ignorance of available alternatives.” 
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Commonwealth v. Collins, 545 A.2d 882, 886 (Pa. 1988). In Collins, the 

defendant was convicted of aggravated assault for firing a shotgun at the 

victim, Barfield. The defendant argued that trial counsel provided ineffective 

assistance by failing to cross-examine Barfield as to her bias against the 

defendant. The defendant claimed Barfield was biased because a few years

earlier, her son had been convicted for the shooting death of the defendant’s

cousin based on the testimony of the defendant’s brother. The Supreme Court 

held that trial counsel had a reasonable basis not to bring out Barfield’s bias:

[T]rial counsel fully considered the tactic of impeaching [] Barfield 

according to a theory of revenge-rooted bias, but rejected that 

approach as being more harmful than beneficial to the defendant’s 

position. [I]t was trial counsel’s judgment that the very same 

circumstances which might have infused [] Barfield with an 

appetite for vengeance could have had the same effect on the 

defendant, and could have given him a motive for perpetrating 

the shotgun attack. Although the prosecution did not have to 

establish motive, such would be relevant and further evidence of 

guilt. In light of those considerations, trial counsel took the 

approach that [] Barfield was an honest and sincere person but 

who was mistaken in her identification of the shooter. To reinforce 

that position, and in conjunction with it, counsel sought to prove 

that her client was elsewhere at the time of the shooting.

Id. (citation omitted).

Here, PCRA counsel asked trial counsel whether he considered filing a 

Frye motion to preclude Dr. Wecht’s testimony for lack of generally accepted 

methodology. Trial counsel answered that he objected to Dr. Wecht’s opinion 

on the ground that it did not “relate to a science, skill or occupation beyond 

the knowledge or experience of the average layman,” i.e., a Rule 702(a) 

objection. N.T. PCRA Hearing, 12/5/17, at 53-54. Trial counsel admitted that 
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he did not consider a Frye motion under Rule 702(c) because he thought he 

was “on such solid footing” with his Rule 702(a) objection. Id. at 60. Thus, 

unlike defense counsel in Collins, trial counsel did not have a reasonable 

excuse for failing to raise a Frye objection. He simply failed to consider Frye 

at all. 

A Frye motion under Rule 702(c) would not have impaired the Rule 

702(a) motion that counsel prosecuted. Instead, a Rule 702(c) motion 

challenging Dr. Wecht’s methodology would have been a natural companion 

to the Rule 702(a) motion. See Commonwealth v. Boykin, 461 A.2d 1101, 

1102 (Pa. 1983) (counsel had no reasonable basis not to request severance 

of defendant’s trial from co-defendants, where “[defendant’s] case may have 

benefited substantially from severance and because making such a motion 

[did] not eliminate or put at risk any available alternative”); cf. People v. 

Wilson, 164 A.D.3d 1012, 1020 (N.Y. App. Div. 2018) (no reasonable basis 

existed for trial counsel’s failure to request Frye hearing to exclude state’s 

expert, where expert’s computer program that used mathematics and 

statistics to analyze DNA data was novel science, expert provided the only 

definitive DNA analysis connecting defendant to the crimes against victim, and 

state’s case would have been weakened had expert’s opinion been found 

unreliable after Frye hearing).

c) Prejudice
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A PCRA petitioner establishes prejudice by demonstrating that 

“counsel’s chosen course of action had an adverse effect on the outcome of 

the proceedings.” Commonwealth v. Chambers, 807 A.2d 872, 883 (Pa. 

2002). “The defendant must show that there is a reasonable probability that, 

but for counsel’s unprofessional errors, the result of the proceeding would 

have been different.” Id. “A reasonable probability is a probability sufficient 

to undermine confidence in the outcome.” Id. “[A] criminal defendant 

alleging prejudice must show that counsel’s errors were so serious as to 

deprive the defendant of a fair trial, a trial whose result is reliable.” Id.

In our opinion, trial counsel’s failure to lodge a Frye objection to Dr. 

Wecht’s testimony deprived Appellant of a fair trial. Dr. Wecht’s testimony 

was essential to the Commonwealth’s case, a fact the Commonwealth 

admitted by certifying in its pretrial appeal that the order precluding Dr. 

Wecht’s testimony substantially handicapped its case. A reasonable 

probability exists that the Commonwealth would not have obtained a guilty 

verdict without Dr. Wecht’s testimony. The Commonwealth accused Appellant 

of strangling Walsh to death from behind in her apartment on September 1, 

1979. Police detectives did not find any signs of semen on Walsh’s body, her 

nightgown, on the top sheet or the fitted sheet from the bed, on the tie that 

bound her hands, or on the ligature. Appellant admitted having sexual 

intercourse with Walsh in her apartment several times earlier in the summer, 

but he asserted he was in another residence several miles away on the 
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morning of Walsh’s death. Over thirty years later, the State Police found 

Appellant’s seminal DNA on the top sheet that covered Walsh’s body, the belt 

tied around her hands, and her nightgown. Dr. Wecht testified that the 

“topographical distribution” of these three areas of sperm positioned Appellant 

on top of Walsh’s back at the time of her death. No other witness testified as 

to the significance of the seminal fluid locations as they related to the time of 

Walsh’s death. Indeed, every forensic expert who testified during trial—

including Dr. Wecht at certain points in his testimony—conceded that it is 

impossible to date DNA samples. Without Dr. Wecht’s topographical

distribution testimony, the Commonwealth had no other evidence purporting 

to prove that the DNA deposits took place around the time of Walsh’s death. 

In view of Appellant’s sexual relationship with Walsh, the jury might well have 

concluded that, but for Dr. Wecht’s testimony, the DNA deposits occurred 

during one or more sexual episodes earlier in the summer. Only through his

testimony was the Commonwealth able to persuade the jury that Appellant 

was the murderer.

Our Supreme Court cautioned in Topa that “scientific proof may in some 

instances assume a posture of mystic infallibility in the eyes of a jury of 

laymen.” Id., 369 A.2d at 1282. Further, as now-Chief Justice Saylor once 

observed:

Expert witnesses can have an extremely prejudicial impact on the

jury, in part because of the way in which the jury perceives a 

witness labeled as an expert. To the jury an “expert” is just an 

unbridled authority figure, and as such he or she is more 
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believable. A witness who has been admitted by the trial court as 

an expert often appears inherently more credible to the jury than 

does a lay witness. . . . Added to the potentially prejudicial 

influence of the term expert is the difficulty inherent in evaluating 

scientific evidence.

Commonwealth v. Smith, 995 A.2d 1143, 1177 n.4 (Pa. 2010) (Saylor, J., 

concurring and dissenting) (citing E.I. du Pont de Nemours & Co. v. 

Robinson, 923 S.W.2d 549, 553 (Tex.1995)). Our review convinces us that 

the testimony of Dr. Wecht—whom the Commonwealth presented as a witness 

who had “seen it all” and therefore was the ultimate voice of authority on 

forensic pathology—prejudiced Appellant in the manner cautioned against in 

Topa and Smith.

V. Conclusion

Our analysis leads us to conclude that the PCRA court erred in denying 

Appellant relief. We do not reach this decision lightly. This case involves a 

heinous crime that snuffed out the life of a young and blameless woman. 

Decades after the victim’s death, the Commonwealth went to considerable 

lengths to solve the crime with cutting-edge technology. A renowned forensic 

pathologist, Dr. Wecht, presented expert testimony on behalf of the 

Commonwealth that, on the surface, appeared to pinpoint Appellant as the 

wrongdoer. 

Nevertheless, the record establishes that the verdict was the product of 

ineffective assistance of trial counsel. Although Dr. Wecht’s testimony was 

not supported by generally accepted methodology, trial counsel failed to move 
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to exclude Dr. Wecht’s testimony under Frye. Counsel did not have a 

reasonable excuse for failing to take this step; he simply neglected to consider 

it. Dr. Wecht’s testimony prejudiced Appellant by serving as the centerpiece 

of the Commonwealth’s case. The jury likely found Appellant guilty because 

Dr. Wecht’s status as an expert added luster to his theory of “topographical 

distribution.” We believe that there is a reasonable probability the outcome 

of this case may well have been different had trial counsel moved to preclude 

Dr. Wecht’s testimony under Frye. For these reasons, we reverse the order 

denying PCRA relief and remand for a new trial in which expert testimony 

concerning “topographical distribution” shall not be admissible.

Order reversed. Case remanded for further proceedings in accordance 

with this opinion. Jurisdiction relinquished.

President Judge Panella joins the opinion.

Judge McLaughlin concurs in the result. 

Judgment Entered.

Joseph D. Seletyn, Esq.

Prothonotary

Date: 4/6/2020