COURT OF APPEALS OF VIRGINIA 

Present: Chief Judge Moon, Judges Benton and Elder 

Argued at Richmond, Virginia 

TONY BERNARD BROWN 

 MEMORANDUM OPINION* BY 

v. Record No. 0074-94-1 JUDGE LARRY G. ELDER 

 JUNE 27, 1995 

COMMONWEALTH OF VIRGINIA 

 FROM THE CIRCUIT COURT OF THE CITY OF CHESAPEAKE 

E. Preston Grissom, Judge 

 Stephen P. Givando (James T. Wise, on brief), 

 for appellant. 

 Eugene Murphy, Assistant Attorney General 

 (James S. Gilmore, III, Attorney General, 

 on brief), for appellee. 

 Tony Bernard Brown (appellant) appeals his convictions for 

one count of rape in violation of Code § 18.2-61; one count of 

abduction in violation of Code § 18.2-47; one count of robbery in 

violation of Code § 18.2-58; and one count of assault and battery 

in violation of Code § 18.2-51. On appeal, appellant contends 

(1) the trial court erred in limiting his cross-examination of 

the Commonwealth's DNA expert, (2) that there was insufficient 

evidence to support his convictions because the DNA testing 

procedure and evidence obtained therefrom were unreliable, and 

(3) the Commonwealth failed to prove a proper chain of custody of 

semen and blood samples. Because we hold that the trial court 

 

 *Pursuant to Code § 17-116.010 this opinion is not 

designated for publication. 
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committed no error, we affirm appellant's convictions. 

 On October 4, 1989, Heidi Purdy (the victim) was awakened by 

an intruder in her Chesapeake house. Although it was dark, the 

victim could see the intruder's arm and ascertain that he was a 

black male. The intruder forced the victim to engage in vaginal 

intercourse, and after unsuccessfully attempting to take the 

victim's stereo system, he fled. Nineteen months later, 

appellant was arrested and charged with the rape, abduction, 

robbery, and assault and battery of the victim. At trial, the 

victim positively identified appellant as someone with similar 

characteristics as the man who raped her. 

 A PERK kit was prepared on the night of the attack, and 

testimony detailed the kit's chain of custody. Mr. Richard 

Guerrieri, an expert in DNA analysis who worked for the Tidewater 

Regional Crime Laboratory, performed DNA analysis on biological 

specimens taken from the kit. On May 22, 1991, two vials of 

blood drawn from appellant were also sent to the Tidewater 

laboratory for the purpose of comparing the blood's DNA with the 

DNA taken from the underwear worn by the victim on the night of 

the attack. 

 During the course of the trial Mr. Guerrieri testified that, 

based on DNA testing, it was possible to eliminate 99.9999 

percent of the black population as the perpetrator; the 

percentage of the population that could have matched the DNA 

pattern found by Guerrieri was .00013 percent. The trial court 
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ruled that Mr. Guerrieri could not be confronted on crossexamination with a scientific report that he did not accept as 

authoritative in the scientific field. At the court's request, 

appellant made a proffer as to what the report would have shown. 

 Appellant presented no expert witnesses on his behalf. 

 On May 5, 1993, at the conclusion of the evidence, the jury 

found appellant guilty of rape, abduction, robbery, and assault 

and battery, but not guilty of burglary. 

 I. 

LIMIT ON CROSS-EXAMINATION 

 First, we hold that the trial court did not err in limiting 

appellant's ability to cross-examine Mr. Guerrieri, the 

Commonwealth's DNA expert witness. Appellant attempted to crossexamine Mr. Guerrieri by using the Report of the Committee on DNA 

Technology in Forensic Science ("the Report"), issued by the 

National Research Council of the National Academy of Science in 

April of 1992. However, Mr. Guerrieri refused to recognize the 

Report as a standard authority within his field of expertise. We 

are guided by the well-accepted rule, as recently articulated by 

the Supreme Court of Virginia, that it is improper to allow the 

"cross-examination of an expert with an article that the expert 

does not recognize as standard and authoritative in a particular 

field." Griffett v. Ryan, 247 Va. 465, 473-74, 443 S.E.2d 149, 

154 (1994). Therefore, the trial court did not err in deciding 

that Mr. Guerrieri could not be cross-examined with the use of 
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the Report. 
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 II. 

RELIABILITY OF DNA TESTING PROCEDURE 

 Appellant contends that the DNA testing procedure and 

evidence obtained therefrom, and the population statistics used 

to reach the testing results, are unreliable and insufficient to 

support a finding that appellant was the perpetrator. As the 

Supreme Court of Virginia recently stated, "DNA testing is a 

reliable scientific technique." Satcher v. Commonwealth, 244 Va. 

220, 241, 421 S.E.2d 821, 834 (1992), cert. denied, __ U.S. __, 

113 S. Ct. 1319 (1993); Spencer v. Commonwealth, 238 Va. 275, 

289, 384 S.E.2d 775, 782 (1989), cert. denied, 493 U.S. 1036 

(1990). Moreover, in 1990, the reliability of DNA evidence and 

its admissibility as evidence in the courts of Virginia was 

codified in Code § 19.2-270.5. 

 In this case, Mr. Guerrieri, the Commonwealth's DNA expert, 

detailed the procedures used to test the DNA samples and 

testified as to the population data bases commonly used by 

laboratories to reach statistical conclusions about the 

probability of a DNA "match." While appellant confronted Mr. 

Guerrieri on cross-examination with matters that may have called 

into question DNA testing's reliability and validity, "[a]ny 

controversy over the results of the testing and the statistical 

calculations goes to the weight of the evidence and is properly 

left to the trier of fact." State v. Anderson, 881 P.2d 29, 48 

(1994). 
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 Mr. Guerrieri testified that he could not eliminate 

appellant as the source of the semen based on the DNA testing 

results; the victim testified that she was attacked by a black 

male (appellant was a black male); and appellant was similar in 

size to the victim's attacker. Viewing this credible evidence in 

the light most favorable to the party prevailing below, we hold 

that the Commonwealth established the intruder's identity beyond 

a reasonable doubt. 

 III. 

CHAIN OF CUSTODY 

 Lastly, assuming that appellant is not procedurally barred 

from raising this issue on appeal by Rules 5A:18 or 5A:12, we 

hold that the Commonwealth sufficiently established a chain of 

custody for both the semen and blood samples. Appellant 

presented no evidence that either sample was contaminated or that 

there was a break in the Commonwealth's chain of custody. The 

Commonwealth's proof of chain of custody included "a showing with 

reasonable certainty that the item[s] [were] not altered, 

substituted or contaminated prior to analysis, in any way that 

would affect the results of the analysis." Reedy v. 

Commonwealth, 9 Va. App. 386, 388, 388 S.E.2d 650, 651 (1990) 

(citation omitted). Keeping in mind that "'[t]he Commonwealth is 

not required to exclude every conceivable possibility of 

substitution, alteration, or tampering,'" id. at 392, 388 S.E.2d 

at 653, we hold that the trial court did not abuse its discretion 
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in allowing the introduction of the DNA test results. 

 For the foregoing reasons, we affirm appellant's 

convictions. 

Affirmed.
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BENTON, J., dissenting. 

 I. 

 "The Due Process Clause protects the accused against 

conviction except upon proof beyond a reasonable doubt of every 

fact necessary to constitute the crime with which he is charged." 

In Re Winship, 397 U.S. 358, 364 (1970). The evidence in this 

case failed to prove beyond a reasonable doubt that Brown was the 

perpetrator of the offense. 

 The Commonwealth's DNA expert, Richard A. Guerrieri, 

testified as follows: 

 Q Now, it's important in calculating these 

figures that we understand exactly what they 

mean. And by that question what I am saying 

is you are not by any stretch of the 

imagination identifying Tony Brown as being 

the person who deposited that semen inside of 

[the victim's] underwear? 

 A I'm not. Jurors, this technique is not 

done to identify an individual as the 

depositor of the stain. But rather I'm doing 

the test to determine if I can eliminate the 

person that I've been asked to compare. 

 Q And not being able to eliminate means that 

he might be the contributor of the stain? 

 A Essentially what it means in the instance 

we can eliminate a very large percentage of 

the population that could not have been the 

depositor. But, no, we could not eliminate 

Mr. Brown. 

 The evidence in this case rises no higher than that 

testimony. 

 Based upon a statistical extrapolation, Guerrieri testified 

that "Brown cannot be eliminated as a possible donor" of the 
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material from which he extracted the DNA. Although he testified 

that statistically he "could eliminate 99.9999 percent of the 

black population" of the United States as donors of the sample, 

he also testified that the "[p]ercentage of [the black 

population] who could have donated the stain with the exclusion 

of . . . Brown would be approximately .00013 percent." In short, 

statistically, 130 persons out of each one million persons in the 

black population of the United States could donate the stain. 

 Moreover, Guerrieri gave no statistics for the probability 

of a match within the Hispanic population or any other population 

group that includes people with dark skins. The victim testified 

that she could only see her attacker's arm. Based upon seeing 

his arm, she reported to the police that her attacker was "a 

black person." Thus, the DNA statistical assumptions are based 

upon the victim's assumption regarding the attacker. 

 Furthermore, the statistical evidence did not take into 

account DNA profiles of persons related to Brown. Guerrieri 

testified that his statistical "percentage is based on unrelated 

individuals to Mr. Brown." Thus, his testimony did not exclude 

persons related to Brown. 

 "[C]ircumstances of suspicion, no matter how grave or 

strong, are not proof of guilt sufficient to support a verdict of 

guilty." Clodfelter v. Commonwealth, 218 Va. 619, 623, 238 

S.E.2d 820, 822 (1977). At best, the Commonwealth's proof relies 

upon an inference drawn from statistical probability. However, 
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it is fundamental that "even a probability of guilt . . . is 

insufficient to support a criminal conviction." Bishop v. 

Commonwealth, 227 Va. 164, 170, 313 S.E.2d 390, 393 (1984). On 

its face, the evidence in the record "is insufficient to exclude 

a reasonable hypothesis that someone other than [Brown] was the 

criminal agent." Christian v. Commonwealth, 221 Va. 1078, 1083, 

277 S.E.2d 205, 208 (1981). The victim's testimony that Brown 

appeared to be the same height and weight as her attacker did not 

exclude persons other than Brown. Without some further proof 

linking Brown to the attack, "the evidence is insufficient to 

carry the Commonwealth's case from the realm of probability and 

supposition into the area of proof beyond a reasonable doubt." 

Hall v. Commonwealth, 225 Va. 533, 537, 303 S.E.2d 903, 905 

(1983). For these reasons, I would reverse the conviction. 

 II. 

 The Commonwealth proffered Guerrieri as an expert "DNA 

examiner." After the trial judge ruled that Guerrieri was 

qualified as a DNA expert, Guerrieri testified on direct 

examination concerning the theory of DNA, the characteristics of 

DNA, the details of DNA analysis, and aspects of population 

genetics. 

 Guerrieri also testified on cross-examination that the 

population data he used to compute the probability of a "match" 

were derived from a data base collected by the F.B.I. He also 

acknowledged that the Report of the National Research Council of 
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the National Academy of Science recommends the use of a 

statistical approach different than that used by his laboratory. 

 When the Commonwealth objected to the defense counsel 

questioning Guerrieri regarding the N.A.S. Report, the trial 

judge ruled that "[t]he question is whether or not [the N.A.S. 

Report has] been recognized in the field of forensic science." 

Guerrieri then responded as follows regarding the N.A.S. Report: 

 Q I would ask first of all, are you familiar 

with the work of the National Research 

Counsel? 

 A Yes. 

 Q And the council operating under the name 

of the National Academy of Science was 

commissioned back in 1990, I believe, to do a 

study of the DNA analysis and interpretation 

of the results, correct? 

 A That is correct. 

 Q And that resulted in the publication of 

the study in 1992? 

 A Yes. 

 Q And contained in that study -- first of 

all, the members of the National Research 

Council would have included the people who 

are experts in the fields of the DNA 

analysis, molecular biology, population 

genetics, all of those things? 

 A Yes, a variety of fields. 

 Q And when they published that study, one of 

the recommendations contained within it was 

that a more conservative figure be used in 

calculating the likelihood of the random 

match. And their principle that they 

endorsed was known as the [ceiling] 

principle, correct? 

 A That was one of their recommendations, 
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yes. 
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* * * * * * * 

 Q Is it not true that the National Academy 

of Science may well be the most prestigious 

collection of scientists in this country? 

 A If you're asking in general, yes. If 

you're asking with applications for forensic 

science to what the work is, then I would 

have a different answer. 

 Q You would give a different answer 

concerning forensic scientists? 

 A My answer would be no. 

 Q Now, is that your opinion or is it an 

opinion that is shared throughout the 

community by other forensic scientists? 

 A It's a universal opinion of forensic 

laboratories. 

 In further response to questioning by the trial judge, 

Guerrieri testified as follows: 

 Q To clear my mind then, is the work 

recognized as a standard authority in your 

field of forensic science in relation to DNA 

testing? 

 A It's debated. It's not universally 

accepted, but it's debated. 

 Q Are you saying that it is standard or not 

standard? 

 A No, it's not standard. It's just argued 

whether it should be accepted as being 

standard. 

 The witness was proffered as an expert in DNA and testified 

as such. I believe that the trial judge's ruling denying counsel 

the right to question Guerrieri regarding the N.A.S. Report was 

based upon the erroneous premise that the N.A.S. Report had to be 
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standard in the field of forensic science. Guerrieri was 

qualified, however, as an expert in DNA. His testimony was 

sufficient to establish that the N.A.S. Report was standard in 

the field of DNA. Thus, I would hold that the testimony was 

sufficient to allow counsel to examine Guerrieri concerning the 

N.A.S. Report. 

 I dissent.