Filed 5/31/16 P. v. Howell CA6

NOT TO BE PUBLISHED IN OFFICIAL REPORTS

California Rules of Court, rule 8.1115(a), prohibits courts and parties from citing or relying on opinions not certified for 

publication or ordered published, except as specified by rule 8.1115(b). This opinion has not been certified for publication 

or ordered published for purposes of rule 8.1115. 

IN THE COURT OF APPEAL OF THE STATE OF CALIFORNIA

SIXTH APPELLATE DISTRICT

THE PEOPLE,

Plaintiff and Respondent,

v.

TREVOR RICHARD HOWELL,

Defendant and Appellant.

 H040885

 (Santa Clara County

 Super. Ct. No. C1241247)

After a day of work as a landscaper, Felipe Avalos had just changed into his 

sandals and had opened the trunk of his car to put away his work boots when he was 

severely beaten by an unknown assailant armed with a large metal object. Based on 

eyewitness descriptions, police apprehended defendant Trevor Richard Howell on a 

nearby trail. A jury convicted defendant of attempted murder (Pen. Code, §§ 187, 664, 

subd. (a)),

1

and it found true the allegations that he had personally used a deadly or 

dangerous weapon (§ 12022, subd. (b)(1)) and had personally inflicted great bodily injury 

(§§ 1203, 12022.7, subd. (a)). Defendant admitted that he had suffered one prior strike

conviction (§§ 667, subds. (b) – (i), 1170.12 ), one prior serious felony conviction 

(§§ 667, subd. (a)), and one prior conviction for which he had served a prison term 

(§ 667.5, subd. (b)). The court sentenced defendant to 24 years in prison. 

 

1

Further statutory references are to the Penal Code unless otherwise indicated.
2

On appeal, defendant contends the trial court erred by precluding him from crossexamining the prosecution’s DNA expert about a Santa Clara County criminal case that 

was ultimately dismissed at the request of the district attorney (the Anderson case). He 

also contends he was not allowed to question his own DNA expert on direct examination 

about that case. Because one theory in the Anderson case (as reported in the news media)

was that DNA evidence relied upon to charge Anderson had been accidentally 

contaminated by a paramedic who had treated both Anderson and the victim on the day 

of the crime, defendant argues it was prejudicial error for the court to exclude references 

to the Anderson case in his examination of the DNA experts. He also argues the court 

erred in prohibiting his counsel from referring to the Anderson case during closing 

argument.

We conclude the trial court did not abuse its discretion by prohibiting defendant 

from examining the DNA experts about the Anderson case or by precluding his counsel 

from referring to the case in closing argument. We will therefore affirm the judgment.

FACTUAL BACKGROUND

I. Prosecution Evidence

A. The Assault

On August 17, 2012, at approximately 3:00 p.m., Felipe Avalos and his foreman, 

Heriberto Garcia, had finished some landscaping work in Cupertino and had returned to 

their employer, Martina Landscaping, at 811 Camden Avenue in Campbell. After 

parking the company truck in the yard, Garcia went inside the office. Avalos went to his 

car, where he took off his work boots and put on sandals. As he opened the trunk of his 

car, he noticed over his right shoulder a person about 100 feet away walking toward him. 

The man was wearing a gray sweatshirt and black pants. Avalos did not pay attention to 

the man because a number of people walk in that area. As he was placing the boots in his 

trunk, Avalos heard the sound of someone running toward him. As he turned, he saw the 

same man with something shiny in his right hand that appeared to be a metal object of 
3

two and one-half to three feet in length. The man struck Avalos on the right side of the 

head with the object. 

As the man continued to strike Avalos on the head, Avalos tried unsuccessfully to 

fend him off by pushing and hugging him. Avalos asked the man, “ ‘Why are you hitting 

me?’ ” The man did not respond. Avalos then slipped and fell as he tried to run away. 

Before falling, he estimated he was struck 10 to 15 times. While Avalos was on the 

ground, his assailant continued to strike him even more forcefully. Avalos tried to cover 

his head with his hands, which absorbed many of the blows. Avalos was struck on the 

ground more times than when he had been standing. At some point, the assailant grabbed 

Avalos by the shirt with his left hand. Avalos called out for help and then saw a car stop 

next to him. He heard a woman tell the assailant to leave Avalos alone. The assailant 

then ran off. 

The woman who came to Avalos’s assistance, Richelle Valone, was driving south 

on Camden Avenue on her way home at approximately 3:20 p.m. As she drove around

the corner, she saw a man striking another man on the head three or four times with what 

appeared to be a hammer. The victim’s face was covered with blood. Valone stopped 

the car approximately eight to nine feet in front of them, threw up her arms, and said,

“ ‘What are you doing?’ ” When she stopped the car, she could see both men out of the 

front windshield. The assailant took off running, passing by the front of Valone’s car. 

The assailant then crossed the street to the parking lot of another business. Valone called 

911. 

Avalos bled profusely. Blood covered his face and was on his clothing. He said 

his head “felt like [] it was going to explode because of all the swelling.” An ambulance 

arrived shortly after the attack and transported him to the Santa Clara Valley Medical 

Center (VMC) emergency room. The medical staff checked for skull fractures and closed 

several head wounds with staples. Avalos was discharged from the hospital after about 

three or four hours. In addition to injuries to his face and head, Avalos sustained a 
4

scratch on his left shoulder that he believed had occurred when his assailant grabbed his 

shirt with his left hand. Avalos testified that his head hurt worse the day after the attack. 

Avalos returned to work one month later, but was still in pain. At the time of trial—one 

year after the attack—Avalos continued to suffer headaches, including migraines. 

B. Apprehension of Defendant

On the afternoon of August 17, 2012, Officer Terry Gallagher of the Campbell 

Police Department was dispatched to a reported assault with a suspect who was fleeing 

the scene. She left the station immediately on her motorcycle and went to a location that 

was at the perimeter of where the suspect was believed to have fled. She went to the Los 

Gatos Creek trail that runs from north to south from Hamilton Avenue in San José to 

Knowles Drive at the border of Los Gatos. The trail is used as a recreation area for 

running, cycling, and walking. As she was riding south on the west side of the trail, she 

passed a man walking north. The man’s clothing matched the suspect’s description. 

After passing the man, Officer Gallagher stopped and turned her motorcycle 

around to watch him. She obtained an updated description of the suspect from dispatch

that indicated he was “a white male with a gray or white hooded sweatshirt[,] dark pants, 

dark shoes[,] about 5 [feet] 8 [inches], medium build,” possibly having a goatee. Based 

upon this updated description, Officer Gallagher drove her motorcycle back toward 

defendant and detained him. He was wearing dark pants of a jean-type material and a 

dark tank top. Although it was not the kind of attire she would associate with running, 

Officer Gallagher observed that defendant was sweating and seemed to be out of breath. 

The location where Officer Gallagher detained defendant was between one-quarter and 

one-half mile from 811 Camden Avenue. Based upon her 18 years of experience in 

patrolling the Campbell area, Officer Gallagher opined that a person could have travelled 

on foot from 811 Camden to the area where defendant was stopped within the time that 

had elapsed between the initial dispatch and when she encountered defendant. 
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After stopping defendant, Officer Gallagher noticed that he had some scrapes on 

both the insides and the knuckles of his hands. She searched him, whereupon she found

tissue in defendant’s front pocket that appeared to have blood on it. 

C. Identification

Valone, the woman who interrupted the attack, described the assailant as wearing 

a dark pullover sweatshirt with a hood and dark black pants. When she encountered the 

assailant during the attack, she observed only part of his face (from the bridge of the nose 

down). When the assailant ran by her, she got a direct view of his face from a distance of 

approximately three and one-half feet from the front of her car. The man was Caucasian, 

in his 40’s, had a somewhat slender build, was approximately five feet eight inches to 

five feet nine inches in height, and had a goatee. 

An officer responding to the scene transported Valone to a location five to ten 

minutes away to see if she could identify the person who had been stopped by Officer 

Gallagher on the trail. The officer stopped his patrol car 30 to 50 feet from the suspect. 

Valone did not get out of the patrol car. Instead, she viewed the suspect through the 

window of the patrol car and through a cyclone fence that was between them. Valone 

testified that when she viewed the person at that time, although he was not wearing a 

sweatshirt, she “felt that it was [the assailant].” She told the officer that, on a scale of one 

to ten (with ten being the most certain), her degree of certainty was seven or eight. 

Valone also identified defendant in court as the assailant, again indicating that her level 

of certainty was a 7 or 8 out of 10.

During cross-examination, Valone admitted that she had told the 911 operator the 

assailant was in his 30’s, she could not recall his ethnicity, and she did not know whether

he had facial hair. Valone also admitted that she did not immediately recognize 

defendant as the assailant at the preliminary hearing. At that hearing, she could not 

estimate the assailant’s age, and she thought defendant’s facial hair was thinner than the 

assailant’s. 
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Avalos testified that his assailant wore a gray sweatshirt with a hood that covered 

his head and forehead. He could only see the man’s face from about the bridge of the 

nose to his chin. Avalos described him as a white male who had a sunburn, a thin nose, 

and a brown goatee. He was between 30 and 40 years old, between five-feet-eight inches 

to six feet tall, and had a thin build. On the evening of the attack, after receiving

treatment at the hospital, Avalos went to the Campbell Police station where he was 

unable to identify defendant as his assailant. He told the police that defendant had the 

same build and the same pants as his assailant, but defendant was not wearing the 

sweatshirt the assailant had worn so it was difficult to identify defendant as the person 

who had attacked him. 

On cross-examination, Avalos agreed that he had told the police that defendant’s 

pants looked like a different fit than the ones worn by his assailant. Avalos also told the 

officers that he thought his attacker was shorter than defendant and had a thinner 

mustache. When asked in court whether defendant looked similar to his assailant, Avalos 

responded: “The height, the type of body, slim. And the face. Slim face. What I was 

able to see from this part of the chin but it is very difficult for me to tell you a straight 

answer, if it is or if it is not that person.” 

D. Forensic Evidence

1. Police Agent Martin Rivera

Police Agent Martin Rivera has been a law enforcement officer with the Campbell 

Police Department for 17 years. He has received over 200 hours of training in the field of 

evidence collection and has worked at over 100 crime scenes for the purpose of collecting 

evidence. “Virtually all” of the evidence collection classes Agent Rivera attended 

included instruction in the collection of DNA evidence. He has personally collected 

DNA evidence at between 50 to 100 crime scenes. 

On the afternoon of August 17, 2012, Rivera was called by a sergeant to the scene 

of the assault at 811 Camden Avenue. While there, Rivera took several photographs and 
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collected some blood samples from the driveway. In collecting the blood samples, he 

wore gloves, and he used sterile Q-tips that had been submerged in sterile water. He

placed the samples into a paper bag. He then returned to the police station and placed the 

samples into a locker for drying.

After completing this task, Rivera went to VMC to meet with Avalos. Before 

meeting with him, Rivera washed his hands and put on a new pair of gloves. Rivera

photographed Avalos and, after observing scratch marks on his left shoulder and back, 

Rivera photographed them and took swab samples of the scratch marks. He did so 

because there is the possibility of DNA being transferred when one person is scratched by

another. It is also possible that DNA from the victim may have been transferred under 

the suspect’s fingernails. He also took a buccal swab from the inside of Avalos’s mouth 

to be used later by the Santa Clara County Crime Laboratory (Crime Lab) to create 

Avalos’s DNA profile. In taking the samples, Rivera washed his hands, put on a new 

pair of latex gloves, and used sterile Q-tips that are packaged separately in sterile 

packaging. Rivera took the DNA samples and articles of Avalos’s clothing to a separate 

location––the police evidence drying room at the Campbell Community Center. 

Rivera next went back to the police station to meet with defendant in a holding 

cell. Before meeting with defendant, Rivera washed his hands and put on a new pair of 

gloves. He explained to defendant that the police would be taking some samples and 

collecting some evidence from him. Before taking samples, Rivera photographed 

defendant, including his hands to document scrape marks on them. Rivera swabbed each 

of defendant’s fingernails and the scrapes on his hands. He also took scrapings from 

underneath defendant’s fingernails and took a buccal swab from the inside of defendant’s 

mouth. Each of the samples was placed in a separate envelope, and each envelope was 

then placed in a separate, second envelope. The envelopes were all placed into a locked 

evidence locker to dry at the police station, which was a different location from where 

Avalos’s DNA samples were stored. 
8

The next day, Rivera returned to the police station. After washing his hands and 

putting on new pair of gloves, he folded the envelopes containing defendant’s samples 

and sealed them closed with tape. Rivera then went to the police drying building at the 

Campbell Community Center. There, he washed his hands, put on new pair of gloves, 

and sealed the envelopes containing Avalos’s samples. 

2. Criminalist Alan Dixon

Alan Dixon is a criminalist with the Crime Lab. He has been a criminalist since 

2005. Before commencing work with the Crime Lab in March 2012, Dixon was a 

criminalist for one year with the Oakland Police Department, a forensic scientist for three 

years with Applied Biosystems (a firm that develops forensic DNA typing technologies 

used in crime laboratories worldwide), and a criminalist for two and one-half years at the 

Georgia Bureau of Investigation’s Division of Forensic Sciences. He performed DNA 

analyses from various samples received from the Campbell Police Department related to 

this case. The samples included buccal swabs from Avalos and defendant, right-hand 

nail swabs and scrapings from defendant, left-hand nail swabs and scrapings from 

defendant, and a swab from Avalos’s back. Dixon generated a report of his forensic 

analysis that was reviewed by two other Crime Lab scientists. 

From Dixon’s analysis of defendant’s right-hand nail swab, he concluded that 

defendant was the major male source of the DNA profile, with a secondary DNA 

contributor at levels too low to perform “any type of meaningful inclusions or exclusions 

of those particular samples.” Dixon found that Avalos was the sole source of DNA from 

the swab taken from Avalos’s back. From his analysis of defendant’s left-hand fingernail 

swab, Dixon determined that the sample contained a mixture of DNA from at least three 

individuals, at least two being male. After including defendant as a potential DNA 

contributor given the source of the swab, Dixon deduced that Avalos was the second 

male contributor to the sample. The mixture ratio of the DNA from defendant and 

Avalos in the sample was nearly equal. Dixon opined that “[t]he probability of finding 
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this collection of alleles [for which he associated Avalos as the contributor] . . . at random 

in the population” was 1 in 74 quadrillion for the Caucasian population, 1 in 12 

quadrillion for the Hispanic population, and 1 in 2.2 quintillion for the African-American 

population. 

II. Defense Evidence

A. Defense Expert Marc Taylor

Marc Taylor is a forensic scientist who testified as an expert on behalf of 

defendant. He owns and operates Technical Associates, Inc. (TAI), a laboratory in 

Ventura. The majority of TAI’s work involves DNA analysis, mostly for defense 

attorneys. TAI’s work includes (1) reviewing and evaluating testing that has been done 

by other laboratories, usually in connection with a specific criminal case, (2) determining 

whether the conclusions drawn from the testing are appropriate, and (3) identifying any 

potential problems with the testing. TAI’s work often includes the retesting of DNA 

samples. 

Taylor and TAI did not perform any DNA analysis or testing in this case. From 

the materials he reviewed, Taylor agreed with Dixon’s analysis and test results. Taylor

testified there were ways in which the DNA samples in this case could have been

contaminated during the laboratory process. He said contamination could have occurred 

in the amplification process, depending upon whether the samples were kept and handled 

separately during the process. But he also testified that during the extraction process, if 

personnel at the Crime Lab had handled samples separately at different times, as was 

indicated in the logs, there should have been no contamination. 

Taylor also testified there were various ways in which the DNA samples may 

become contaminated in the field, and he was aware of specific instances of DNA 

contamination as a result of objects being taken from place to place or by having the 

same person collect different samples at several locations. He said the blood samples 

taken from the scene, the sample from scratches on Avalos’s back, and the buccal swabs 
10

taken from Avalos at the hospital were each potential sources for the contamination of the 

samples taken from defendant’s fingernails. Taylor postulated that Police Agent Rivera, 

by handling the same camera at all three locations (i.e., the scene of the crime, the 

hospital, and the holding cell), could have transferred DNA to contaminate the samples

taken from defendant. Specifically, Taylor noted that Rivera used his camera in the 

hospital with the same gloved hands he used to take samples from Avalos, thereby 

creating the possibility of contamination of subsequent samples that were taken. He also 

suggested that a sample could have been contaminated if Rivera had used his cell phone 

at one of the locations, transferred DNA onto it, and later transferred the DNA while 

taking a sample at a different location. And he testified that the fact that Rivera went to 

each of the three locations, of itself, furnished the possibility of contamination of the 

samples taken from defendant at the holding cell. On cross-examination, Taylor 

reiterated that there was a possibility of DNA having been contaminated in the field, but

he indicated he had no way of assessing the likelihood or probability of such 

contamination. 

B. Dr. Robert Shomer

Dr. Robert Shomer is an experimental psychologist who has testified as an expert 

on the subject of eyewitness identification. Dr. Shomer opined that the identification of 

strangers “has the lowest reliability of eyewitness identification.” He testified that the 

more specific the initial description of the stranger by the eyewitness, the more likely he 

or she would be able to differentiate the stranger from other similar-looking people. 

Stated otherwise, the less detail about the stranger the eyewitness has initially, the greater 

the “possibility of mistaking [the stranger] for somebody that looks similar.” Other 

factors that reduce reliability include where (1) there is cross-racial identification; (2) the 

witness’s attention is divided; (3) the stranger is moving; (4) the event is sudden; and 

(5) the circumstances of the event are stressful. Dr. Shomer also testified that in-field 

show-up identifications are “considered to be inherently suggestive” and have “a high 
11

rate of error.” He also opined that the “top of the head is critical more so than other areas 

of the face,” so that the ability of a witness to identify a stranger in a show-up would be 

impaired where the witness initially observed the stranger wearing a hooded sweatshirt 

that obscured part of the face.

III. Stipulated Evidence

A stipulation was read to the jury that, based upon video surveillance footage 

retrieved by Campbell Police Officer Ramirez defendant entered a Safeway store at 

2341 Winchester Boulevard in Campbell in August 17, 2012, at approximately 2:49 p.m., 

and he exited the store at approximately 2:55 p.m. Defendant appeared to be carrying a 

white shirt or bag. Counsel further stipulated that a piece of rebar was found at 811 

Camden Avenue on August 18, 2012. The rebar was booked into evidence. “Laboratory 

testing of the rebar yielded no DNA or other relevant results.” 

PROCEDURAL BACKGROUND

Defendant was charged by information filed October 25, 2012, with attempted 

murder (§ 664, subd. (a), § 187; count 1), and assault with a deadly weapon (§ 245, 

subd. (a)(1); count 2). It was further alleged as to count 1 that defendant acted willfully, 

deliberately, and with premeditation (§§ 664, 187, 189), and that he personally used a 

deadly weapon (§ 12022, subd. (b)(1)). As to both counts, it was alleged that defendant 

personally used a deadly weapon (§§ 667, 1192.7) and personally inflicted great bodily 

injury (§§ 12022.7, subd. (a), 667, 1192.7). It was also alleged that defendant had 

suffered a prior strike conviction (§§ 667, subd. (b)/1170.12), a prior serious felony 

conviction (§ 667, subd. (a)), and a prior felony conviction for which he had served a 

prison term (§ 667.5, subd. (b)). 

After a trial by jury, defendant was convicted on August 20, 2013, of attempted 

murder. The jury found true the allegations that defendant personally used a dangerous 

or deadly weapon and that he personally inflicted great bodily injury. The jury found not 

true the allegation that defendant acted willfully, deliberately, and with premeditation. 
12

Defendant waived his right to a trial of the strike prior, serious felony prior, and prison 

prior allegations, and he admitted those allegations. 

After denying defendant’s motion for the court to exercise its discretion to dismiss 

the prior strike allegation under People v. Superior Court (Romero) (1996) 

13 Cal.4th 497, the court sentenced defendant to a term of 24 years. The sentence was

based upon the midterm of seven years for attempted murder, doubled due to defendant’s 

prior strike, plus one year for the weapon-use enhancement, three years for the great 

bodily injury infliction enhancement, five years for the prior strike conviction, and one

year for the prison prior. 

DISCUSSION

I. No Error in Court’s Exclusion of Anderson Case Evidence

A. Background

Defendant’s claims of error concern the propriety of the trial court’s rulings 

precluding any reference by defense counsel to the Anderson case in (1) the crossexamination of the prosecution’s DNA expert, Alan Dixon, (2) the examination of the 

defense’s DNA expert, Marc Taylor, and (3) closing argument. 

To properly raise an appellate challenge to the exclusion of evidence, the 

proponent of the evidence must have made an offer of proof or other sufficient showing 

to the trial court in support of admission of the evidence. (People v. Vines (2011) 

51 Cal.4th 830, 869.) “The offer of proof must address the ‘substance, purpose, and 

relevance of the excluded evidence’ (Evid. Code, § 354, subd. (a)), and must set forth the 

actual evidence to be produced and not merely the facts or issues to be addressed and 

argued [citation]. The trial court may reject a general or vague offer of proof that does 

not specify the testimony to be offered by the proposed witness. [Citations.]” (People v. 

Carlin (2007) 150 Cal.App.4th 322, 334; see also People v. Foss (2007) 155 Cal.App.4th 

113, 127-128.) 
13

The record before us concerning the circumstances of the Anderson case was 

exhibit 2, which consisted of two June 2013 newspaper articles from the San José

Mercury News and a July 2013 opinion article from the New York Times. We will deem 

this to be defendant’s offer of proof. As gleaned from that exhibit, on 

November 30, 2012, Raveesh Kumra died of suffocation at his home in Monte Sereno 

after being bound and gagged during a home invasion robbery perpetrated by several 

suspects. Five suspects were arrested, including Lukis Anderson, who was described as a 

transient. Although not indicated in the newspaper articles, it is apparent from the 

dialogue between the trial court and the prosecutor in the instant case that Anderson was 

an acquaintance of other suspects who were arrested in connection with the Kumra home 

invasion and murder. 

According to criminalist Tahnee Mehmet Nelson, Anderson’s DNA was found 

underneath the fingernails of Kumra. But Anderson was released from custody and 

charges against him were dismissed in June 2013 because his attorney had shown that 

Anderson, on the evening of Kumra crime, was being treated at VMC. Anderson had 

been transported to VMC from downtown San José after he lost consciousness due to 

intoxication. One of the theories explaining the presence of Anderson’s DNA on the 

victim was that the same paramedic who pronounced Kumra dead in his home had 

transported Anderson to VMC several hours earlier. A second theory involved DNA 

transfer from a jacket, and a third involved Anderson having been placed in a holding cell 

with an associate of another suspect in the November 30, 2012 crime. The criminal case 

against three of the other defendants charged in the Kumra home invasion 

robbery/homicide was ongoing at the time of trial in this case

Before testimony commenced in this case, defense counsel argued that he was 

entitled to discovery regarding the Anderson case, specifically the analysis in that case

concerning the presence of Anderson’s DNA on Kumra. Counsel asserted that the 

requested material showed “inherent vulnerability and weakness [of DNA testing] that 
14

tends to favor Mr. Howell in this case.” He argued the material was discoverable and the 

defense should be permitted to use the DNA analysis to cross-examine the People’s DNA 

expert. 

The prosecutor responded that information about the Anderson case was not 

relevant. He represented that he had spoken with the deputy district attorney who had 

handled the Anderson case. The prosecutor argued that the criminalists were not the 

same in the two cases, and in the present case, there was a videotape record of most of the 

evidence collection efforts performed by Police Agent Rivera. In addition, the prosecutor 

represented that the Crime Lab director had conducted an internal investigation and had 

“concluded there was no cross-contamination in [the Anderson] case.” 

The court denied defendant’s request for discovery relating to the Anderson case, 

saying there was “no similarity at all between this case and the Anderson case.”2 The 

court then ruled that the Anderson case was “completely irrelevant.” But it also said the 

defense could “present any [DNA] transfer theories as supported by the evidence,” and it 

noted that the defense intended to call “experts in this case who can talk about possible 

[DNA] transfer without the Anderson case.” 

During cross-examination of the People’s DNA expert (Dixon), defense counsel 

attempted to inquire about “a recent high profile case” involving contamination of DNA 

samples. The court sustained the prosecution’s objection to the inquiry. In later 

proceedings held outside the presence of the jury, defense counsel again argued the 

relevance of the Anderson case in cross-examining Dixon. He acknowledged that 

because he had not obtained discovery, he did not know whether the DNA transfer 

attributed to Anderson resulted from cross-contamination in the field or in the laboratory. 

The court again ruled that the Anderson case was not relevant. 

 

2 Defendant does not challenge the trial court’s ruling denying his request for 

discovery concerning the Anderson case. 
15

Before calling his own DNA expert witness (Taylor), defense counsel argued that 

he should be permitted to include in his examination the circumstances of the Anderson

case as representing a documented case of in-field DNA contamination. The court 

confirmed, based on its prior rulings, that defense counsel would not be allowed to refer 

to the Anderson case, “which we have no information on as to exactly what happened . . . 

and [whether] it was in [the] field as opposed to in the lab [that there may have been 

contamination].” 

After the parties rested, defense counsel requested that the court permit him to 

mention the Anderson case during closing argument. He asserted it was “in the common 

knowledge of the jurors” since the case had been reported in newspapers. The prosecutor 

opposed the request, responding that (1) it was an attempt to raise facts not in evidence, 

(2) the Anderson case could not be deemed common knowledge simply because it had 

been reported in the newspapers, and (3) its introduction was objectionable under 

“[Evidence Code section] 352 grounds [because] it’s confusing [and] speculative.” The 

court ruled that defense counsel could not refer to the Anderson case during his closing 

argument. 

B. Applicable Law and Standards of Review

Only evidence that is relevant is admissible. (Evid. Code, § 350.) “ ‘Relevant 

evidence’ means evidence, including evidence relevant to the credibility of a witness or 

hearsay declarant, having any tendency in reason to prove or disprove any disputed fact 

that is of consequence to the determination of the action.” (Evid. Code, § 210.) “ ‘The 

test of relevance is whether the evidence tends “logically, naturally, and by reasonable 

inference” to establish material facts such as identity, intent, or motive. [Citations.]’ 

[Citation.]” (People v. Bivert (2011) 52 Cal.4th 96, 116-117, quoting People v. Garceau

(1993) 6 Cal.4th 140, 177.) “Accordingly, a ‘witness may not be examined on matters 

that are irrelevant to the issue in the case.’ [Citation.]” (People v. Lewis (2001) 

25 Cal.4th 610, 640.) The trial court also has the discretionary power to exclude 
16

“evidence if its probative value is substantially outweighed by the probability that its 

admission will (a) necessitate undue consumption of time or (b) create substantial danger 

of undue prejudice, of confusing the issues, or of misleading the jury.” (Evid. Code, 

§ 352.) 

A trial court’s ruling on the admissibility of evidence is reviewed for abuse of 

discretion. (People v. Harris (2005) 37 Cal.4th 310, 337.) Although the court “ ‘has 

broad discretion in determining the relevance of evidence [citations] . . . , [it] lacks 

discretion to admit irrelevant evidence.’ [Citations.]” (People v. Riggs (2008) 44 Cal.4th 

248, 289 (Riggs).) Likewise, the trial court has “broad discretion to weigh the prejudicial 

impact of testimony against its probative value.” (People v. Lancaster (2007) 41 Cal.4th 

50, 83.) Thus, “ ‘[t]he trial court has broad discretion both in determining the relevance 

of evidence and in assessing whether its prejudicial effect outweighs its probative value.’ 

[Citation.]” (People v. Jones (2011) 51 Cal.4th 346, 373, quoting People v. Horning

(2004) 34 Cal.4th 871, 900.) An abuse of discretion occurs where it is shown that “ ‘the 

trial court exercised its discretion in an arbitrary, capricious, or patently absurd manner 

that resulted in a manifest miscarriage of justice.’ [Citation.]” (People v. Carrington

(2009) 47 Cal.4th 145, 195; see also People v. Osband (1996) 13 Cal.4th 622, 666 [abuse 

of discretion occurs when trial court’s “ruling ‘falls outside the bounds of reason’ ”].)

Generally, an expert witness may base his or her opinion on hearsay (People v. 

Pollock (2004) 32 Cal.4th 1153, 1172 (Pollock)), or upon hypothetical facts (People v. 

Boyette (2002) 29 Cal.4th 381, 449). (See Evid. Code, § 801, subd. (b).) But the matter 

relied upon must “provide a reasonable basis for the particular opinion offered.” 

(Lockheed Litigation Cases (2004) 115 Cal.App.4th 558, 564.) And “[a]n expert opinion 

may not be based on conjectural or speculative matters. [Citation.]” (Howard 

Entertainment, Inc. v. Kudrow (2012) 208 Cal.App.4th 1102, 1115 (Howard 

Entertainment).) The trial court exercises broad discretion in ruling on evidentiary issues 

concerning expert testimony. (Pollock, at p. 1172; see also Maatuk v. Guttman (2009) 
17

173 Cal.App.4th 1191, 1197 (Maatuk) [court has “broad discretion in ruling on 

foundational matters on which expert testimony is to be based”].) Thus, a trial court may 

properly exclude in the examination of an expert “any hearsay matter whose irrelevance, 

unreliability, or potential for prejudice outweighs its proper probative value.” (People v. 

Montiel (1993) 5 Cal.4th 877, 919.) Likewise, the trial court properly sustains objections 

to expert testimony where it is based “ ‘on assumptions of fact without evidentiary 

support [citation], or on speculative or conjectural factors.’ ” (People v. Richardson

(2008) 43 Cal.4th 959, 1008.)

“It is settled that the trial court is given wide discretion in controlling the scope of 

relevant cross-examination.” (People v. Farnam (2002) 28 Cal.4th 107, 187 (Farnam); 

see also People v. Capistrano (2014) 59 Cal.4th 830, 866 [trial court “has wide latitude to 

restrict” cross-examination of witnesses].) This wide discretion will be disturbed on 

appeal “ ‘[o]nly [upon a showing of] a manifest abuse of the court’s discretion.’ 

[Citation.]” (People v. Adan (2000) 77 Cal.App.4th 390, 394.)

C. Exclusion of Anderson Case During Dixon’s Cross-Examination

Defendant contends that the trial court deprived him of his constitutional right to 

present a complete defense by prohibiting him from referring to the Anderson case to 

cross-examine the prosecution’s DNA expert (Dixon). He argues that because “the scope 

of permissible cross-examination [of experts] is quite broad,” and cross-examination may 

include “evidence not previously admitted at trial or that is otherwise admissible,” the 

trial court abused its discretion and prejudicially erred by denying him the opportunity to 

cross-examine Dixon concerning the Anderson case. We disagree.

The proffered evidence was not relevant—it was not evidence “having any 

tendency in reason to prove or disprove any disputed fact that is of consequence to the 

determination of the action.” (Evid. Code, § 210.) As presented in the newspaper 

articles (court’s exhibit 2), the Anderson case differed in many respects from the instant 

case. The suspect, Anderson, had a demonstrated alibi, even though his DNA was at the 
18

crime scene and he was an apparent acquaintance of the other arrestees. He was 

apparently not the subject of eyewitness identification, and he was treated by a paramedic 

the same evening the paramedic tended to the victim (Kumra) at the crime scene. None 

of these facts exist in the instant case. 

Furthermore, while one theory explaining the presence of Anderson’s DNA at the 

crime scene involved a paramedic’s both having treated Anderson and having tended to 

Kumra, this was one of several theories, and had apparently not been proven. And while 

both crimes were committed in Santa Clara County and both involved the Crime Lab, the 

criminalists were not the same. In short, the only matters of commonality between the 

two cases were the county, the Crime Lab, and a theory—unproven in each case—of 

possible contamination in the field of the DNA sample linking the suspect to the crime. 

Thus, the offer of proof presented nothing more than anecdotal evidence of the possibility

of a DNA sample’s contamination in an unrelated Santa Clara County criminal case. The 

trial court—acknowledging its broad discretion in determining both the relevance of 

evidence (Riggs, supra, 44 Cal.4th at p. 289) and in controlling the scope of relevant 

cross-examination (Farnam, supra, 28 Cal.4th at p. 187)—did not abuse its discretion by

prohibiting defense counsel from introducing the circumstances of the Anderson case in 

his cross-examination of Dixon. 

In exercising its discretion to exclude the circumstances of the Anderson case, the 

court indicated it would permit the defense to “present any [DNA] transfer theories as 

supported by the evidence.” In addition to permitting the defense DNA expert (Taylor) 

to testify at length concerning DNA transfer theories (as discussed, post), the court 

allowed defense counsel’s wide-ranging cross-examination of the prosecution’s DNA 

expert (Dixon). Defense counsel, among other things, explored with Dixon the 

possibility that the various DNA samples from the field were contaminated during the 

extraction or amplification process in the Crime Lab. And he emphasized that if a DNA 

sample were somehow contaminated in the field, there would be nothing Dixon could do 
19

about it. Moreover, in his cross-examination of Police Agent Rivera—who qualified at 

trial as an expert in DNA evidence collection—defense counsel inquired about various 

mechanisms by which the DNA sample in question (swab from defendant’s left-hand 

fingernails) may have become contaminated at one of the three collection sites (i.e., the 

crime scene, the hospital, and the police holding cell). He inquired about the possibility 

of a DNA transfer by Rivera’s (1) use of his camera at all three sites; (2) failure to wash 

his hands or take proper precautions in using gloves at the three sites; (3) failure to 

change his clothing during his collection of evidence at the three sites; (4) his collection 

and handling of the victim’s clothing; and (5) use of his cell phone at the holding cell. 

Even assuming the existence of any marginal relevance of the circumstances of the 

Anderson case, the trial court did not abuse its discretion to exclude the evidence under 

Evidence Code section 352, a ground the prosecutor raised when defense counsel sought 

to refer to the Anderson case during closing argument. Assuming the evidence had some 

minimal probative value, it was still excludible under Evidence Code section 352 because 

it would have “necessitate[d] undue consumption of time or . . . confus[ed] the issues, or

misle[d] the jury.” Thus, for instance, in People v. Fuiava (2012) 53 Cal.4th 622, our 

high court concluded that the trial court properly excluded evidence of a federal civil suit 

against sheriff’s deputies offered to show that the murder victim, another deputy, may 

have used deadly force against the defendant that prompted the defendant to shoot him. 

“In the trial court’s view, presenting evidence of the lawsuit and other misconduct by 

other deputies would be going ‘too far afield,’ would ‘sidetrack’ and ‘unduly prolong’ the 

trial, and would ‘invite[ ] the jury to speculate as to what the lawsuit was about.’ ” (Id. at 

p. 662; see also People v. Verdugo (2010) 50 Cal.4th 263, 291 [evidence of detectives’ 

alleged fabrication of evidence in an unrelated case, charges of which they were 

exonerated, properly excluded].) It is well settled that “ ‘ “a ruling or decision, itself 

correct in law, will not be disturbed on appeal merely because given for the wrong 

reason. If right upon any theory of law applicable to the case, it must be sustained 
20

regardless of the considerations which may have moved the trial court to its conclusion.” 

[Citation.]’ [Citation.]” (People v. Zapien (1993) 4 Cal.4th 929, 976 (Zapien), quoting 

D’Amico v. Board of Medical Examiners (1974) 11 Cal.3d 1, 19.) We therefore

conclude—in addition to finding no abuse of discretion in excluding the evidence as not 

relevant—that there was no error during Dixon’s cross-examination in excluding the 

Anderson case under Evidence Code section 352. (See People v. Geier (2007) 41 Cal.4th 

555, 582 (Geier) [holding that, although trial court did not expressly base its ruling on 

that ground, evidence was properly excluded under Evidence Code § 352].)

D. Exclusion of Anderson Case During Taylor’s Direct Examination

Defendant contends the trial court deprived him of his constitutional right to 

present a complete defense by prohibiting him from using the Anderson case to examine 

his DNA expert, Marc Taylor. He asserts the court’s order precluding him from

examining Taylor concerning the circumstances of the Anderson case was an abuse of 

discretion. He argues that because the Anderson case constituted evidence that “was 

properly within the scope of expert testimony,” and the defense theory of the DNA 

contamination (through Rivera’s handling of several samples) “mirrored the facts of the 

[alleged DNA contamination in the Anderson] case as reported by the [two newspapers],”

the evidence should have been allowed. Defendant contends the error was prejudicial,

requiring reversal. We disagree.

As noted in part I.C., ante, the Anderson case was not relevant. The evidence 

from that case did not “hav[e] any tendency in reason to prove or disprove any disputed 

fact that is of consequence to the determination of the action.” (Evid. Code, § 210.) It

offered only a theory of possible contamination of a DNA sample in a criminal case with 

circumstances dissimilar from those here. Because the DNA contamination theory in the 

Anderson case could be deemed a “conjectural or speculative matter[]” (Howard 

Entertainment, supra, 208 Cal.App.4th at p. 1115), it was proper to exclude it as 

foundational material that could not “provide a reasonable basis for the particular opinion 
21

offered.” (Lockheed Litigation Cases, supra, 115 Cal.App.4th at p. 564.) Exercising its 

broad discretion in determining both the relevance of evidence (Riggs, supra, 44 Cal.4th 

at p. 289) and in ruling on evidentiary questions concerning expert testimony (Pollock, 

supra, 32 Cal.4th at p. 1172; Maatuk, supra, 173 Cal.App.4th at p. 1197), the court did 

not abuse its discretion by prohibiting defense counsel from introducing the 

circumstances of the Anderson case during his direct examination of Taylor.

We note that the trial court permitted a broad and extensive presentation by the 

defense DNA expert on the subject of DNA transfer or contamination. On that subject, 

Taylor testified, among other things, that there were many ways DNA can be transferred, 

and the level of DNA concentration may vary depending on the nature of the transfer and 

how much DNA was on the person before the transfer. Taylor explained in detail the 

various mechanisms by which DNA samples taken by Rivera in this case could have been 

contaminated at different stages of their analysis at the Crime Lab. He was also 

examined in detail about a number of mechanisms by which the DNA samples could 

have been contaminated in the field, including through Rivera’s use of his camera and 

cell phone at different stages of the collection process. 

E. Exclusion of the Anderson Case During Closing Argument

Defendant contends the trial court deprived him of his constitutional right to 

present a complete defense by prohibiting him from using the Anderson case during 

closing argument. He argues that the Anderson case, although not in evidence, involved 

a matter of “common knowledge” such that it was a proper matter of argument by 

defense counsel.

We first address defendant’s contentions concerning the proper standard of 

review. Defendant contends that the court’s exclusion of the newspaper articles during 

closing argument “automatically constitutes error.” Elsewhere in his opening brief, he 

argues the exclusion “automatically requires reversal.” In support of his position that a 

stringent standard of review should be applied, defendant cites People v. Woodson (1964) 
22

231 Cal.App.2d 10 (Woodson). He argues that Woodson supports the proposition that “a 

court’s restriction on the use of relevant newspaper or magazine articles during closing 

argument necessarily constitutes error, so long as it is otherwise relevant within the 

proper scope of argument.” (Italics added.) But as we have already noted, the trial 

court’s determination of whether material is relevant from an evidentiary standpoint is a 

highly discretionary matter (Riggs, supra, 44 Cal.4th at p. 289), and in this instance the 

court did not abuse that discretion in excluding the evidence concerning the Anderson 

case. 

In any event, we do not read Woodson to hold that the trial court is restricted in its 

ability to make rulings limiting the proper scope of argument by counsel. To the 

contrary, the trial court is vested with discretion pursuant to section 1044 to limit 

counsel’s argument as necessary under the circumstances of the particular case. (People 

v. London (1988) 206 Cal.App.3d 896, 909 (London).) We therefore conclude that under 

the circumstances presented here—i.e., where the court makes a limited intrusion into the 

substance of counsel’s argument, as opposed to one in which the court significantly 

curtails such argument—the trial court’s ruling is reviewed for abuse of discretion. (See 

People v. Ponce (1996) 44 Cal.App.4th 1380, 1388 (Ponce); People v. West (1983) 

139 Cal.App.3d 606, 611 (West) [“whether a particular newspaper or magazine article 

should be read to the jury, is a matter that is addressed to the sound discretion of the trial 

court”].)

Although a criminal defendant is afforded wide latitude in his or her closing 

argument (People v. Farmer (1989) 47 Cal.3d 888, 922 (Farmer), overruled on another 

point in People v. Waidla (2000) 22 Cal.4th 690, 724, fn. 6), “it is improper to state facts 

that are not in evidence during summation, with certain narrow exceptions such as 

commonly known matters. [Citation.]” (Farmer, at p. 922.) Thus, defense counsel may 

not allude in argument to matters that have not been introduced into evidence. (See 

People v. Stankewitz (1990) 51 Cal.3d 72, 102 [argument that prosecution had failed to 
23

call more than one witness to the shooting, even though three others were available, was 

improper where nothing in the record indicated three other witnesses were available]; 

Farmer, at p. 922 [defense argument raising prosecution’s position in another case was 

improper].) Since there was no evidence concerning the Anderson case introduced at 

trial—and the proposed introduction of such evidence was properly denied by the trial 

court—the court did not err in instructing defense counsel not to refer to the Anderson

case during his closing argument. 

Contrary to defendant’s contention, the Anderson case was not a matter of 

common knowledge, making it a permissible subject for closing argument. As our high 

court noted long ago, “ ‘Matters of common knowledge—being things not special to the 

case in hearing—may, like the language itself, be parcel of the woven argument which 

the advocate lays before the jury.’ ” (People v. Molina (1899) 126 Cal. 505, 508.) Thus, 

“[c]ounsel’s summation to the jury ‘must be based solely upon those matters of fact of 

which evidence has already been introduced or of which no evidence need ever be 

introduced because of their notoriety as judicially noticed facts.’ [Citations.] He [or she] 

may state matters not in evidence that are common knowledge, or are illustrations drawn 

from common experience, history, or literature. [Citations.] He [or she] may not, 

however, under the guise of argument, assert as facts matters not in evidence or excluded 

because inadmissible. [Citations.]” (People v. Love (1961) 56 Cal.2d 720, 730 (Love), 

disapproved on other grounds in People v. Morse (1964) 60 Cal.2d 631, 637, fn. 2.)

The Anderson case was not a matter of common knowledge. As the trial judge 

noted, “[the Anderson case is] certainly not within any common knowledge of the jury. I 

would be surprised if any of the jurors were aware of it . . . .” And particularly since the 

Anderson case was properly excluded as evidence during trial, its attempted introduction 

during closing argument ran afoul of the principle that counsel “may not . . . under the 

guise of argument, assert as facts matters not in evidence or excluded because 

inadmissible. [Citations.]” (Love, at p. 730.)
24

Defendant points to several cases in which appellate courts concluded that certain 

magazine and newspaper articles were appropriate subjects for closing argument. (See, 

e.g., People v. Guzman (1975) 47 Cal.App.3d 380, 392, disapproved on other grounds in 

People v. McDonald (1984) 37 Cal .3d 351, 362, fn. 8; West, supra, 139 Cal.App.3d at 

p. 610; Woodson, supra, 231 Cal.App.2d at pp. 15-16; People v. Travis (1954) 

129 Cal.App.2d 29.) Those cases reflect instances in which the trial court exercised its 

discretion under particular circumstances. But there is no general rule to the effect that 

attorneys may refer to newspaper or magazine articles in closing argument, and, as noted, 

the trial court in its discretion may limit counsel’s argument as necessary pursuant to 

section 1044. (London, supra, 206 Cal.App.3d at p. 909; see also Ponce, supra, 

44 Cal.App.4th at pp. 1387-1389 [trial court has responsibility to prevent improper 

argument by all parties, including attempts to present factually unsubstantiated 

contentions to jury].)

Although during closing argument counsel may “refer the jury to nonevidentiary 

matters of common knowledge, or to illustrations drawn from common experience, 

history, or literature [citation], . . . he [or she] may not dwell on the particular facts of 

unrelated, unsubstantiated cases.” (People v. Mendoza (1974) 37 Cal.App.3d 717, 725 

(Mendoza) [trial court properly denied defense counsel license to read newspaper 

clippings about unrelated crimes, hearsay material which could only confuse the jury 

with irrelevant facts]; see also Farmer, supra, 47 Cal.3d at pp. 921-922 [court properly 

prohibited defense counsel from reading from article when contents were not revealed 

prior to argument]; People v. Pelayo (1999) 69 Cal.App.4th 115, 122 (Pelayo) [trial court 

properly restricted defense counsel’s argument by prohibiting reference to newspaper 

articles about suspect ultimately acquitted of sex crimes against children after discovery 

that alleged victims fabricated the allegations].)

Here, defense counsel sought to refer to a case not drawn from common 

knowledge. That case involved an unsubstantiated claim of improper DNA evidence 
25

transfer in the field by a paramedic, which was one of at least three theories concerning 

the manner in which the accused’s DNA was found at the crime scene. Although 

reference to the Anderson case was excluded, defense counsel was permitted to explore at 

length in his closing argument the crux of his theory concerning the DNA evidence 

pointing to his client’s guilt: that the defendant’s left fingernail sample purporting to 

show both defendant’s and the victim’s DNA was contaminated during the evidence 

collection process. The trial court, in the exercise of its discretion under section 1044 to 

control counsel’s argument, did not abuse its discretion in prohibiting reference to the 

Anderson case during closing argument. (Pelayo, supra, 69 Cal.App.4th at p. 122; 

Mendoza, supra, 37 Cal.App.3d at p. 725.)

F. Cumulative Error

Defendant argues in the alternative that even if the errors he claims occurred were 

not enough to warrant reversal, the cumulative effect of such alleged errors was 

prejudicial. This argument has no merit, “there being no error to cumulate.” (People v. 

Watkins (2012) 55 Cal.4th 999, 1036.)

DISPOSITION

The judgment is affirmed.
 

Márquez, J.

WE CONCUR:

 

Rushing, P.J.

 

Grover, J.

People v. Howell

No. H040885