Title: People v. Valencia
Citation: N/A
Docket Number: S250218
State: California
Issuer: California Supreme Court
Date: July 1, 2021

IN THE SUPREME COURT OF 
CALIFORNIA 
 
THE PEOPLE, 
Plaintiff and Respondent, 
v. 
JOSE LUIS VALENCIA, 
Defendant and Appellant. 
 
S250218 
 
Fifth Appellate District 
F072943 
 
Kern County Superior Court 
LF010246B 
________________________________________________________ 
 
THE PEOPLE, 
Plaintiff and Respondent, 
v. 
EDGAR ISIDRO GARCIA, 
Defendant and Appellant. 
 
S250670 
 
Fifth Appellate District 
F073515 
 
Kern County Superior Court 
LF010246A 
 
July 1, 2021 
 
Justice Corrigan authored the opinion of the Court, in which 
Chief Justice Cantil-Sakauye and Justices Liu, Cuéllar, 
Kruger, Groban, and Jenkins concurred.   
 
1 
PEOPLE v. VALENCIA* 
S250218
 
Opinion of the Court by Corrigan, J. 
 
This case involves allegations of active gang participation 
(Pen. Code, § 186.22, subd. (a)) and gang enhancements (Pen. 
Code, § 186.22, subd. (b)) attached to other offenses.  The 
charges require proof that a gang’s members have engaged in “a 
pattern of criminal gang activity” (Pen. Code, § 186.22, subd. 
(f)), defined, in part, as the commission of two or more 
enumerated offenses (Pen. Code, § 186.22, subd. (e)).  We hold 
that the commission of such crimes, also known as predicate 
offenses, must be proven by independently admissible evidence.  
Under the authority of People v. Sanchez (2016) 63 Cal.4th 665 
(Sanchez), such proof may not be established solely by the 
testimony of an expert who has no personal knowledge of facts 
otherwise necessary to satisfy the prosecution’s burden.  The 
judgment of the Court of Appeal, reaching the same conclusion, 
is affirmed.   
I.  BACKGROUND 
Early on the morning of August 24, 2014, Jose B. and 
Alejandro P. sat on the tailgate of a truck at a carwash in the 
City of Arvin.  Multiple shots were fired.  One round struck Jose 
in the leg and others hit the truck tires.  Coincidentally, an 
officer on patrol near the carwash happened to see a pickup 
driving slowly with its lights off, then saw seven to 10 muzzle 
 
*  
Consolidated with People v. Garcia (S250670). 
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
2 
flashes coming from the front passenger window.  Shining a 
light on the pickup, the officer saw defendant Jose Luis Valencia 
behind the wheel and defendant Edgar Isidro Garcia in the 
passenger seat.  An hour-long vehicle chase ensued, during 
which Garcia threw something from the truck’s window.  The 
cylinder of a revolver was later recovered in that vicinity.  
Defendants were ultimately arrested, and gunshot residue was 
found on the front passenger door of the pickup.   
Both defendants were charged with two counts of 
attempted murder, assault with a firearm, and active street 
gang participation.1  Garcia was also charged with shooting 
from a vehicle.2  Valencia was charged with evading an officer 
and knowingly allowing a passenger to shoot from the truck.3  
Gang and firearm enhancements were attached to the various 
charges.4   
Arvin Police Officer Ryan Calderon testified as a gang 
expert.  A nine-year department veteran, he had specialized in 
gang enforcement for five and a half years and had personally 
investigated about 200 crimes involving the Arvina 13 gang.  
Calderon testified about the gang, describing its monikers, 
graffiti, tattoos, colors, and territory, which included the 
 
1  
Penal Code sections 187, subdivision (a), 189, subdivision 
(a), 664, subdivision (a), 245, subdivision (a)(2), 186.22, 
subdivision (a).   
2  
Penal Code section 26100, subdivision (c).   
3  
Vehicle Code section 2800.2, subdivision (a); Penal Code 
section 26100, subdivision (b).   
4  
Penal Code sections 186.22, subdivision (b)(1), 12022.5, 
subdivision (a), 12022.53, subdivisions (c), (d), (e)(1), 12022.55, 
12022.7, subdivision (a).   
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
3 
carwash.  Arvina 13’s primary felonious activities include 
shootings, assaults, burglaries, and drug sales.   
In Officer Calderon’s opinion, Valencia and Garcia were 
Arvina 13 gang members, based on their tattoos and police 
contacts.  In response to a hypothetical question, Calderon 
testified that defendants’ conduct benefitted Arvina 13 by 
creating community fear and gang notoriety.  Calderon also 
related the facts of three predicate offenses committed by Arvina 
13 gang members:  a 2008 assault by Jose Arredondo, a 2010 
assault by Adam Arellano, and a 2013 attempted robbery and 
assault by Orion Jimenez.  Calderon’s only knowledge of these 
offenses came from conversations with other officers and a 
review of police reports.  Certified copies of court documents 
related to the convictions in each case were admitted into 
evidence, including the pleadings and court minute orders.   
Defendants’ first trial ended when the jury hung on almost 
all charges.5  A second jury convicted defendants of the 
remaining allegations.  Both men were sentenced to extended 
prison terms.6  The Court of Appeal held that some of the 
expert’s testimony about the predicate offenses constituted 
inadmissible hearsay.  It reversed the active gang participation 
 
5  
The jury convicted Valencia of evading an officer but 
deadlocked on the remaining charges as to both defendants.   
6  
The court sentenced Garcia to two terms of 15 years to life 
on the two attempted murder counts, plus 25 years to life for 
firearm discharge causing great bodily injury, and 20 years for 
firearm discharge, consecutive, staying the remaining counts.  
Valencia received two life terms for attempted murder and the 
same terms of 25 years to life and 20 years for firearm discharge 
by a principal in a gang offense, with the remaining charges 
stayed.   
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
4 
and enhancement allegations, as well as Valencia’s firearm 
enhancements attached to those allegations, and otherwise 
affirmed the judgments.  (People v. Valencia (July 10, 2018, 
F072943) [nonpub. opn.]; People v. Garcia (July 10, 2018, 
F073515) [nonpub. opn.].)7  We granted the Attorney General’s 
petitions for review and consolidated these two cases for 
decision.8 
II.  DISCUSSION 
The Attorney General argues the gang expert’s recitation 
of hearsay describing the circumstances of the three predicate 
offenses constituted background information about which the 
expert could properly testify.  To resolve this issue, we examine 
the statutory scheme covering gang allegations, our decisions in 
Sanchez and People v. Veamatahau (2020) 9 Cal.5th 16 
(Veamatahau), and Court of Appeal decisions that have 
previously addressed the question.   
 
7  
The Court of Appeal remanded both matters to the trial 
court for retrial on the reversed allegations or, if the People elect 
not to retry them, for resentencing.  The trial court was ordered 
to exercise its discretion whether to strike Garcia’s firearm 
enhancements under newly enacted Senate Bill No. 620 (2017–
2018 Reg. Sess.) (Stats. 2017, ch. 682, §§ 1–2), and Valencia was 
to be allowed to make a record of factors relevant at a future 
youth offender parole hearing (Pen. Code, §§ 3051, 4801, subd 
(c); see People v. Franklin (2016) 63 Cal.4th 261, 283–284).   
8  
We initially granted the People’s petitions for review in 
these cases and held them for People v. Perez (2020) 9 Cal.5th 1 
(Perez), which concluded a defendant’s failure to object did not 
forfeit a Sanchez claim in a case predating that decision.  (See 
id. at pp. 7–14.)  After the Perez decision, we consolidated these 
matters and sought briefing on the current predicate offense 
issue.   
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
5 
A.  The STEP Act 
In 1988, the Legislature enacted the California Street 
Terrorism Enforcement and Prevention Act (STEP Act or Act; 
Pen. Code, § 186.20 et seq.) to eradicate “criminal activity by 
street gangs.”  (People v. Loeun (1997) 17 Cal.4th 1, 4 (Loeun).)  
Underlying the STEP Act was the Legislature’s finding that 
“California is in a state of crisis which has been caused by 
violent street gangs whose members threaten, terrorize, and 
commit a multitude of crimes against the peaceful citizens of 
their neighborhoods.”  (Pen. Code, § 186.21, 2d par.)  The 
Legislature sought to balance the “constitutionally protected 
rights of freedom of expression and association” (id., 1st par.) 
with the need to protect all Californians from the burden of fear, 
intimidation and physical harm caused by gang violence, which 
it found presents “a clear and present danger to public order and 
safety” (id., 1st par.).  The Act was specifically structured to 
protect both free association and public safety.  (See People v. 
Rodriguez (2012) 55 Cal.4th 1125, 1133–1135 (lead opn. of 
Corrigan, J.) (Rodriguez).)   
As relevant here, the STEP Act created a substantive 
offense of active participation “in any criminal street gang” (Pen. 
Code, § 186.22, subd. (a)), and a sentencing enhancement for a 
felony committed “for the benefit of, at the direction of, or in 
association with any criminal street gang” (Pen. Code, § 186.22, 
subd. (b)(1)).  (See Rodriguez, supra, 55 Cal.4th at p. 1130 (lead 
opn. of Corrigan, J.); see also id. at p. 1130, fn. 5 (lead opn. of 
Corrigan, J.).)  The Act defines such a gang as “any ongoing 
organization, association, or group of three or more persons, 
whether formal or informal, having as one of its primary 
activities the commission of one or more [enumerated offenses], 
having a common name or common identifying sign or symbol, 
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
6 
and whose members individually or collectively engage in, or 
have engaged in, a pattern of criminal gang activity.”  (Pen. 
Code, § 186.22, subd. (f).)  A “ ‘pattern of criminal gang activity’ ” 
is separately defined as “the commission of, attempted 
commission of, conspiracy to commit, or solicitation of, sustained 
juvenile petition for, or conviction of two or more [enumerated] 
offenses, provided at least one of these offenses occurred after 
the effective date of this [Act] and the last of those offenses 
occurred within three years after a prior offense, and the 
offenses were committed on separate occasions, or by two or 
more persons . . . .”  (Pen. Code, § 186.22, subd. (e).)9  The 
offenses comprising a pattern of criminal gang activity are 
referred to as predicate offenses.  (See Loeun, supra, 17 Cal.4th 
at p. 4.)  We use the term “commission” in this opinion to include 
the broader statutory inclusion of the “attempted commission of, 
conspiracy to commit, or solicitation of, sustained juvenile 
petition for, or conviction” of a predicate offense.  (Pen. Code, 
§ 186.22, subd. (e).)   
Penal Code section 186.22, subdivision (e) does not state 
that a predicate offense must be committed by a gang member.  
However, that requirement derives from the definition of a 
“ ‘criminal street gang,’ ” which includes proof that the gang’s 
“members individually or collectively engage in, or have engaged 
 
9  
The original STEP Act was an urgency measure that went 
into effect on September 26, 1988.  (Stats. 1988, ch. 1242, § 3; 
see People v. Gardeley (1996) 14 Cal.4th 605, 626 (Gardeley), 
disapproved on another ground in Sanchez, supra, 63 Cal.4th at 
p. 686, fn. 13.)  Citations here are to the Act which became 
effective on January 1, 1993.  (Stats. 1989, ch. 930, § 5.1.)  Those 
provisions, by their terms, are repealed as of January 1, 2022, 
to be replaced by an identical provision on that date.  (See Stats. 
2016, ch. 887, § 1; Stats. 2017, ch. 561, § 179.)   
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
7 
in, a pattern of criminal gang activity.”   (Pen. Code, § 186.22, 
subd. (f), italics added.)  It follows, then, that the proof of a 
predicate offense must establish that a member of a defendant’s 
alleged gang was involved in its commission.10  Taken together 
the statutory scheme requires proof that gang members 
committed at least two predicate offenses within the statutory 
timeframe.  Such proof will generally require evidence of who 
committed the crime and when they did so, as well as evidence 
of their gang membership and the nature of the crimes.  How 
those particular facts are proven lies at the heart of this case.   
B.  Sanchez and Veamatahau 
In Sanchez, the defendant was arrested and found to 
possess a gun and drugs packaged for sale.  (Sanchez, supra, 63 
Cal.4th at p. 671.)  He was convicted of drug and firearm 
offenses with attached gang enhancements (Pen. Code, § 186.22, 
subd. (b)(1)) and the substantive offense of active gang 
participation (Pen. Code, § 186.22, subd. (a)).  (Sanchez, at pp. 
671, fn. 1, 673.)  On appeal, he argued that the gang expert was 
erroneously permitted to testify about five prior contacts 
Sanchez had with police.  The expert had no personal knowledge 
 
10  
The requirement that a gang member be involved in a 
predicate offense is to be distinguished from new allegations 
that the charged defendant actively participated in a gang (Pen. 
Code, § 186.22, subd. (a)) or committed a gang enhancement 
(Pen. Code, § 186.22, subd. (b)).  A defendant need not be a gang 
member for those charged allegations to be proven, so long as all 
statutory elements are satisfied.  (See Rodriguez, supra, 55 
Cal.4th at p. 1130 (lead opn. of Corrigan, J.); People v. Valdez 
(2012) 55 Cal.4th 82, 132; Pen. Code, § 186.22, subd. (i).)  
However, before a conviction can be relied on in the future as 
evidence of a predicate offense, there must be evidence that the 
perpetrator was a gang member.  
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
8 
of these contacts but read about them in police reports and other 
sources.  (Id. at p. 673.)  The expert was permitted to testify as 
to the particulars of the police contacts, as described in those 
documents, to explain the basis of his opinion that Sanchez was 
a gang member and committed the charged offenses for the 
gang’s benefit.  (See id. at p. 683; Gardeley, supra, 14 Cal.4th at 
pp. 618–620.)  If offered for the truth of their content, statements 
repeated from those sources would constitute hearsay.  The jury 
was told, however, that the testimony was not admitted for its 
truth but only to explain the basis for the expert’s opinion.  
(Sanchez, at p. 684.)   
In Crawford v. Washington (2004) 541 U.S. 36 (Crawford), 
the United States Supreme Court held that the confrontation 
clause of the federal Constitution generally bars the admission 
of what it termed “testimonial” hearsay when offered by the 
prosecution against a criminal defendant without a showing of 
witness “unavailability and a prior opportunity for cross-
examination.”  (Crawford, at p. 68.)  It clarified, however, that 
out-of-court statements not offered for the truth of their content 
are not hearsay and do not impinge upon the confrontation 
right.  (Id. at pp. 59–60, fn. 9.)  Sanchez addressed “whether 
facts an expert relates as the basis for his opinion are properly 
considered to be admitted for their truth.”  (Sanchez, supra, 63 
Cal.4th at p. 674.)  Sanchez arose at the intersection of the 
hearsay rule, the holdings in Crawford and its progeny, and the 
evidentiary rules applicable to expert testimony.   
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
9 
Hearsay is an out-of-court statement offered to prove the 
truth of its content.11  Ordinarily, hearsay is inadmissible unless 
it falls under a recognized exception.  (Evid. Code, § 1200, subd. 
(b).)  In addition, lay witnesses may only testify about matters 
within their personal knowledge.  (Evid. Code, § 702, subd. 
(a).)12  In the case of experts, both of these general rules are 
applied with greater latitude.  “A person is qualified to testify as 
an expert if he has special knowledge, skill, experience, training, 
or education sufficient to qualify him as an expert on the subject 
to which his testimony relates.”  (Evid. Code, § 720, subd. (a).)  
“An expert may express an opinion on ‘a subject that is 
sufficiently beyond common experience that the opinion of an 
expert would assist the trier of fact.’  (Evid. Code, § 801, subd. 
(a).)  In addition to matters within their own personal 
knowledge, experts may relate information acquired through 
their training and experience, even though that information 
may have been derived from conversations with others, lectures, 
study of learned treatises, etc.”  (Sanchez, supra, 63 Cal.4th at 
p. 675.)  “[A]n expert’s testimony concerning his general 
knowledge, even if technically hearsay, has not been subject to 
exclusion on hearsay grounds.”  (Id. at p. 676.)   
 
11  
The statute defines hearsay as “evidence of a statement 
that was made other than by a witness while testifying at the 
hearing and that is offered to prove the truth of the matter 
stated.”  (Evid. Code, § 1200, subd. (a).) 
12  
“ ‘Personal knowledge’ means a present recollection of an 
impression derived from the exercise of the witness’ own 
senses.”  (Cal. Law Revision Com. com., 29B pt. 2A West’s Ann. 
Evid. Code (2019 ed.) foll. § 702, p. 416.)  “ ‘Perceive’ means to 
acquire knowledge through one’s senses.”  (Evid. Code, § 170.)   
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
10 
Sanchez contrasted general knowledge about facts 
accepted in the expert’s field with “case-specific facts about 
which the expert has no independent knowledge.”  (Sanchez, 
supra, 63 Cal.4th at p. 676.)  “Case-specific facts are those 
relating to the particular events and participants alleged to 
have been involved in the case being tried.”  (Id. at p. 676; see 
further discussion of what constitutes “case-specific facts” in pts. 
C & D, post.)  “Generally, parties try to establish the facts on 
which their theory of the case depends by calling witnesses with 
personal knowledge of those case-specific facts.  An expert may 
then testify about more generalized information, even if derived 
from hearsay, to help jurors understand the significance of those 
case-specific facts.  An expert is also allowed to give an opinion 
about what those facts may mean.  The expert is generally not 
permitted, however, to supply case-specific facts about which he 
has no personal knowledge.”13  (Sanchez, at p. 676.)   
Exploration of an expert’s opinion based on case-specific 
facts outside the expert’s personal knowledge can still be 
accomplished through the use of hypothetical questions:  “An 
examiner may ask an expert to assume a certain set of case-
specific facts for which there is independent competent evidence, 
then ask the expert what conclusions the expert would draw 
 
13  
Education and training often involve statements and 
writings conveyed by teachers and other experts.  In addition, 
however, expert witnesses may acquire knowledge through their 
own experimentation, observations and personal experience. 
(See Evid. Code, § 720, subds. (a), (b); Simons, Cal. Evidence 
Manual (2021) § 4:1, pp. 318–321.) Like any other witness, 
experts can relate what they have personally observed and that 
testimony would not be hearsay.  It can, of course be challenged 
by the opponent, but its admission would not implicate Sanchez 
or the broader hearsay rule.   
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
11 
from those assumed facts.  If no competent evidence of a case-
specific fact has been, or will be, admitted, the expert cannot be 
asked to assume it.  The expert is permitted to give his opinion 
because the significance of certain facts may not be clear to a lay 
juror 
lacking 
the 
expert’s 
specialized 
knowledge 
and 
experience.”  (Id. at pp. 676–677.)   
Although “[a]t common law, the treatment of an expert’s 
testimony as to general background information and case-
specific hearsay differed significantly” (Sanchez, supra, 63 
Cal.4th at p. 678), that treatment evolved after enactment of the 
Evidence Code in 1965:  “Evidence Code section 801, subdivision 
(b) provides that an expert may render an opinion ‘[b]ased on 
matter (including his special knowledge, skill, experience, 
training, and education) perceived by or personally known to the 
witness or made known to him at or before the hearing, whether 
or not admissible, that is of a type that reasonably may be relied 
upon by an expert in forming an opinion upon the subject to 
which his testimony relates, unless an expert is precluded by law 
from using such matter as a basis for his opinion.’  (Italics 
added.)  Similarly, Evidence Code section 802 allows an expert 
to ‘state on direct examination the reasons for his opinion and 
the matter (including, in the case of an expert, his special 
knowledge, skill, experience, training, and education) upon 
which it is based, unless he is precluded by law from using such 
reasons or matter as a basis for his opinion.’ ”  (Sanchez, at p. 
678.)  Where an expert relied upon out-of-court statements to 
explain the bases of an opinion, “[c]ourts [had] created a two-
pronged approach to balancing ‘an expert’s need to consider 
extrajudicial matters, and a jury’s need for information 
sufficient to evaluate an expert opinion’ so as not to ‘conflict with 
an accused’s interest in avoiding substantive use of unreliable 
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
12 
hearsay.’ ”  (Id. at p. 679, quoting People v. Montiel (1993) 5 
Cal.4th 877, 919.)  The jury would be given a limiting instruction 
that “matters admitted through an expert go only to the basis of 
his opinion and should not be considered for their truth.”  
(Montiel, at p. 919.)  The trial court retained discretion to 
exclude the evidence under Evidence Code section 352 if it 
concluded the probative value was substantially outweighed by 
the probability that the jury would ignore the limiting 
instruction and “improperly consider it as independent proof of 
the facts recited therein.”  (People v. Coleman (1985) 38 Cal.3d 
69, 91.)   
Sanchez disapproved the Montiel procedure.  (Sanchez, 
supra, 63 Cal.4th at p. 686, fn. 13.)  “When an expert relies on 
hearsay to provide case-specific facts, considers the statements 
as true, and relates them to the jury as a reliable basis for the 
expert’s opinion, it cannot logically be asserted that the hearsay 
content is not offered for its truth.  In such a case, ‘the validity 
of [the expert’s] opinion ultimately turn[s] on the truth’ 
[citation] of the hearsay statement.”  (Sanchez, at pp. 682–683.)  
Sanchez observed that juries are instructed to decide “ ‘whether 
information on which the expert relied was true and accurate’ ” 
(id. at p. 684, quoting CALCRIM No. 332), and “[w]ithout 
independent competent proof of those case-specific facts, the 
jury simply ha[s] no basis from which to draw such a 
conclusion.”  (Sanchez, at p. 684.)  “Once we recognize that the 
jury must consider expert basis testimony for its truth in order 
to evaluate the expert’s opinion, hearsay and confrontation 
problems cannot be avoided by giving a limiting instruction that 
such testimony should not be considered for its truth.  If an 
expert testifies to case-specific out-of-court statements to 
explain the bases for his opinion, those statements are 
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
13 
necessarily considered by the jury for their truth, thus rendering 
them hearsay.  Like any other hearsay evidence, it must be 
properly admitted through an applicable hearsay exception.  
Alternatively, the evidence can be admitted through an 
appropriate witness and the expert may assume its truth in a 
properly worded hypothetical question in the traditional 
manner.”  (Id. at p. 684, fn. omitted.)   
Sanchez concluded the gang expert related case-specific 
facts.14  “[His] case-specific testimony as to defendant’s police 
contacts was relied on to prove defendant’s intent to benefit the 
Delhi gang when committing the underlying crimes to which the 
gang enhancement was attached.  [He also] recounted facts 
contained in the police reports and STEP notice to establish 
defendant’s Delhi membership.  While gang membership is not 
an element of the gang enhancement [citation], evidence of 
defendant’s membership and commission of crimes in Delhi’s 
territory bolstered the prosecution’s theory that he acted with 
intent to benefit his gang, an element it was required to prove.”  
(Sanchez, supra, 63 Cal.4th at pp. 698–699; see id. at p. 685.)   
In Veamatahau, the defendant was charged with 
possessing contraband pills.  The question at trial was whether 
 
14  
An out-of-court statement about case-specific facts may or 
may not involve “testimonial hearsay,” depending on who made 
the statements, under what circumstances, and for what 
purpose.  (Cf. Ohio v. Clark (2015) 576 U.S. 237, 243–251; Davis 
v. Washington (2006) 547 U.S. 813, 821–832; Crawford, supra, 
541 U.S. at pp. 51–59; People v. Cage (2007) 40 Cal.4th 965, 984; 
Simons, Cal. Evidence Manual (2020) § 2:115.)  One import of 
the Sanchez holding, however, is that out-of-court statements 
offered to prove case-specific facts are hearsay regardless of any 
testimonial character.  (See Sanchez, supra, 63 Cal.4th at pp. 
684–686.)   
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
14 
the recovered pills contained the controlled substance 
alprazolam.  An expert compared markings he saw on the pills 
“against 
a 
database 
containing 
descriptions 
of 
pharmaceuticals.”  (Veamatahau, supra, 9 Cal.5th at p. 22.)  
Asked about the identification process, the expert testified that 
the approach he employed was generally accepted in the 
scientific community.  He elaborated on cross-examination that 
“when ‘there’s a controlled substance in the tablet, the FDA 
[(Food and Drug Administration)] requires companies to have a 
distinct imprint on those tablets to differentiate it from any 
other tablets.  The FDA regulates that.  [¶] And if there’s a tablet 
that has — in this case GG32 — or 249 [as an imprint] — you 
can look that up.  And it’s going to tell you that it contains 
alprazolam, 2 milligrams.  And that’s — we trust that, all those 
regulations being in place, to say that there’s alprazolam in 
those tablets.’ ”  (Id. at p. 23.)  Based on this database search, 
the expert opined the pills contained alprazolam.  (Ibid.)  
Veamatahau concluded that the expert’s testimony about what 
he read from the database was background information.  “[The 
expert’s] statement concerning what the database ‘tell[s] you’ 
related general background information relied upon in the 
criminalist’s field.  The facts disclosed by the database, and 
conveyed by [the expert], are ‘about what [any generic] pills 
containing certain chemicals look like.’  [Citation.]  The 
database revealed nothing about ‘the particular events . . . in the 
case being tried,’ i.e., the particular pills that Sergeant Simmont 
seized from defendant.  [Citation.]  Any information about the 
specific pills seized from defendant came from [the expert’s] 
personal observation (that they contained the logos ‘GG32 — or 
249’) and his ultimate opinion (that they contained alprazolam), 
not from the database.  In short, information from the database 
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
15 
is not case specific but is the kind of background information 
experts have traditionally been able to rely on and relate to the 
jury.”  (Id. at p. 27.)   
Veamatahau clarifies that the distinction between 
background information and case-specific facts can depend, in 
part, on what the evidence, considered independently, is offered 
to prove.  The expert’s testimony about the contents of the 
database, and expert reliance on it, was offered to prove that all 
pills with a given imprint contain alprazolam.  That testimony, 
though hearsay, related background information.  His opinion 
was offered to prove that the defendant’s pills, those at issue in 
the current prosecution, contained alprazolam.  The markings 
on the defendant’s pills were case-specific facts.  The expert was 
permitted to testify about them because his own observation of 
the markings provided personal knowledge.  The jury was 
entitled 
to 
consider 
the 
expert-provided 
background 
information, even though hearsay, along with his personal 
observations and opinion to determine whether the pills the 
defendant possessed contained the controlled substance.  (See 
discussion, post.)   
C.  Distinguishing Background Information from Case-
specific Facts 
In gang cases, drawing the line of demarcation between 
background 
and 
case-specific 
information 
can 
present 
challenges, as reflected by the different conclusions drawn by 
the Courts of Appeal regarding predicate offenses.  Several cases 
have held that predicate offense evidence is merely background 
similar to other kinds of information about gangs, like their 
territory, symbols, and operations, that are generally accepted 
as true by experts in the field.  (See People v. Bermudez (2020) 
45 Cal.App.5th 358, 363; People v. Blessett (2018) 22 Cal.App.5th 
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
16 
903, 944–945, disapproved on another ground in Perez, supra, 9 
Cal.5th at p. 14; People v. Vega-Robles (2017) 9 Cal.App.5th 382, 
410–411; People v. Meraz (2016) 6 Cal.App.5th 1162, 1174–
1175.)  Those cases pointed to language in Sanchez that 
describes case-specific facts as those “relating to the particular 
events and participants alleged to have been involved in the case 
being tried.”  (Sanchez, supra, 63 Cal.4th at p. 676.)  They went 
on to conclude that testimony about predicate offenses merely 
conveyed “historical facts” about the gang’s conduct and 
activities, as opposed to specific facts relating to the events and 
participants involved in the case being tried.  (Blessett, at p. 
944.)  Bermudez opined that “so long as the predicate offenses 
do not involve defendant or individuals involved in the 
defendant’s case[,] [s]uch predicate offenses are chapters in a 
gang’s biography . . . not case-specific information.”  (Bermudez, 
at. p. 363.)   
To determine whether predicate offenses are case-specific 
or background facts, we must look beyond an isolated phrase in 
Sanchez and instead probe the underlying rationale permitting 
experts to rely on and relate certain hearsay.  As Sanchez 
observed, “expert witnesses are given greater latitude” to testify 
regarding background information beyond matters within their 
personal knowledge because their testimony may “provide 
specialized context the jury will need to resolve an issue.”  
(Sanchez, supra, 63 Cal.4th at p. 675.)  Thus, experts are given 
latitude over lay witnesses only to the extent they are conveying 
acquired expertise in their field.  Sanchez explained that “[o]ur 
decision does not call into question the propriety of an expert’s 
testimony concerning background information regarding his 
knowledge and expertise and premises generally accepted in his 
field.  Indeed, an expert’s background knowledge and experience 
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
17 
is what distinguishes him from a lay witness, and, as noted, 
testimony relating such background information has never been 
subject to exclusion as hearsay, even though offered for its truth.  
Thus, our decision does not affect the traditional latitude 
granted to experts to describe background information and 
knowledge in the area of his expertise, even when based on 
hearsay.  Our conclusion restores the traditional distinction 
between 
an 
expert’s 
testimony 
regarding 
background 
information and case-specific facts.”  (Id. at p. 685, italics 
added.)   
Sanchez and Veamatahau make clear that experts are 
given greater latitude to testify about matter beyond their 
personal knowledge because they are allowed to give an opinion 
on subjects “sufficiently beyond common experience that the 
opinion of an expert would assist the trier of fact” (Evid. Code, 
§ 801, subd. (a)), so long as the opinion is based on matter “that 
is of a type that reasonably may be relied upon by an expert in 
forming an opinion upon the subject” (Evid. Code, § 801, subd. 
(b)).  “This latitude is a matter of practicality.  A physician is not 
required to personally replicate all medical experiments dating 
back to the time of Galen in order to relate generally accepted 
medical knowledge that will assist the jury in deciding the case 
at hand.  An expert’s testimony as to information generally 
accepted in the expert’s area, or supported by his own [personal] 
experience, may usually be admitted to provide specialized 
context the jury will need to resolve an issue.”  (Sanchez, supra, 
63 Cal.4th at p. 675.)  Hallmarks of background facts are that 
they are generally accepted by experts in their field of expertise, 
and that they will usually be applicable to all similar cases.  
Permitting experts to relate background hearsay information is 
analytically based on the safeguard of reliability.  A level of 
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
18 
reliability is provided when an expert lays foundation as to facts 
grounded in his or her expertise and generally accepted in that 
field.  In Veamatahau, for example, the hearsay database 
information was accepted by experts in the field as accurately 
stating that pills of a certain appearance contain alprazolam.  
(See Veamatahau, supra, 9 Cal.5th at p. 32.)   
Conversely, if experts give testimony that goes beyond 
their own experience or beyond principles generally accepted in 
their field, the justifications for allowing greater evidentiary 
latitude cease to apply.  One commentator has noted that the 
pre-Sanchez “not in for the truth” approach blurred the line 
between general background knowledge and case-specific fact.  
The previous approach “opened the door to abuse; namely, 
expert witnesses being used as conduits to transmit 
inadmissible hearsay that does not otherwise fall under a 
statutory exception as assertions of fact to the jury.  With such 
a liberal approach to admissibility, there is a risk that damaging 
inadmissible evidence, which would be unable to make its way 
to the jury through the proper channels, could be smuggled to 
the jury through the expert; or worse, parties may offer expert 
testimony simply to place such damaging evidence before the 
fact-finder disguised as expert basis testimony.  The Sanchez 
rule curbs this potential for abuse with its bright-line rule 
prohibiting an expert from relating all case-specific hearsay 
statements forming the basis of the expert’s opinion, unless such 
hearsay statements fall under an applicable hearsay exception 
or are properly admitted independent of the expert’s testimony.”  
(Hamilton, The End of Smuggling Hearsay:  How People v. 
Sanchez Redefined the Scope of Expert Basis Testimony in 
California and Beyond (2018) 21 Chap. L.Rev. 509, 511, fns. 
omitted.)  In other words, case-specific facts are not purged of 
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
19 
their hearsay character just because an expert, rather than a 
lay witness, is asked to repeat them in court.   
The challenge, then, in Sanchez and Veamatahau was to 
accommodate the longstanding rule allowing experts to testify 
about “information generally accepted in the expert’s area” or 
matters “in his field of expertise” (Sanchez, supra, 63 Cal.4th at 
pp. 675, 676), yet restore the rule that experts may not simply 
“regurgitate information from another source” (Veamatahau, 
supra, 9 Cal.5th at p. 34).  Sanchez and Veamatahau used the 
terms “general background information” and “case-specific 
facts” to distinguish, in the context of expert testimony, between 
hearsay that may be admitted because it is generally accepted 
by experts in the field, and facts that cannot be proven by 
hearsay because that reliability justification is absent.15  These 
latter case-specific facts must be proven through the testimony 
of a witness with personal knowledge or by other admissible 
evidence.  (See generally Sanchez, supra, 63 Cal.4th at p. 677.)   
The proper role of expert testimony is to help the jury 
understand the significance of case-specific facts proven by 
competent evidence, not to place before the jury otherwise 
unsubstantiated assertions of fact.  On the other hand, any 
 
15  
In 
this 
sense, 
the 
phrase 
“general 
background 
information” from Sanchez (Sanchez, supra, 63 Cal.4th at p. 
678) is tethered to the concept of information derived from 
hearsay but generally considered accurate in a field of expertise.  
As discussed ante (see p. 10, fn. 13), an expert’s personal 
knowledge, on the other hand, may provide context relevant to 
assist jurors in understanding the facts of a given case (Evid. 
Code, § 801, subd. (a)), but it does not involve the recitation of 
hearsay.  As used in Sanchez the term “general background 
information” refers to expert knowledge derived from hearsay 
that is generally accepted as accurate by experts in the field.   
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
20 
witness, whether lay or expert, may testify to facts within their 
personal knowledge, so long as those facts are relevant.  The 
reliability of those facts is furnished not by general agreement 
among experts in their field, but by the witness’s personal 
knowledge, for which there must be foundation.  In addition, the 
accuracy of that testimony can be tested by cross-examination 
exploring the circumstances under which the witness’s 
knowledge was acquired and whether it is being accurately 
remembered and recounted.  A lay witness need not know the 
significance of the facts or how that significance might be 
explained by an expert, but the witness must have the required 
personal knowledge.   
This conclusion mirrors the facts and analysis from 
Veamatahau.  There, hearsay information from the database 
was properly admitted as background because it was generally 
accepted in the field that the FDA markings were reliable 
indications of the drug’s presence and also that the database 
itself accurately connected the FDA marks with the presence of 
that drug.  (Evid. Code, § 801, subd. (b).)16  Based on those 
hearsay background facts and his own personal observations 
about the markings he saw, the expert formed an opinion to 
which he testified, and on which the jury was entitled to rely, if 
 
16  
The initial burden is on the proponent to lay a foundation 
of general acceptance.  (Cf. Sargon Enterprises, Inc. v. University 
of Southern California (2012) 55 Cal.4th 747, 769–773.)  The 
opposing party is, of course, entitled to challenge the foundation 
by cross-examination or the introduction of contrary evidence.  
The challenge may be brought in limine, renewed through a 
motion to strike, or attacked as unreliable in argument to the 
jury.   
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
21 
they found it to be credible.  (See Veamatahau, supra, 9 Cal.5th 
at pp. 26–35.) 
D.  Predicate Offenses Are Case-specific and Must Be 
Proven by Competent Evidence 
The Attorney General argues that facts used to prove 
predicate offenses are merely background information properly 
supplied by expert testimony.  This argument fails because of 
the nature of the facts themselves, the absence of foundation 
that they are generally accepted as reliable in a field of 
expertise, and the allegations they are being offered to prove.  
As Sanchez observed, general testimony about a gang’s 
behavior, history, territory, and general operations is usually 
admissible.  (See Sanchez, supra, 63 Cal.4th at p. 698.)  The 
same is true of the gang’s name, symbols, and colors.  All this 
background information can be admitted through an expert’s 
testimony, even if hearsay, if there is evidence that it is 
considered reliable and accurate by experts on the gang.   
Such information stands in contrast to information 
regarding the commission of a particular offense on a specific 
occasion.  Experts with no personal knowledge of case-specific 
facts, or who do not rely on other admissible evidence 
establishing those facts, are simply “regurgitat[ing] information 
from another source.”  (Veamatahau, supra, 9 Cal.5th at p. 34.)  
This is the practice rejected in Veamatahau and warned against 
in Sanchez.  “What an expert cannot do is relate as true case-
specific facts asserted in hearsay statements, unless they are 
independently proven by competent evidence or are covered by 
a hearsay exception.”  (Sanchez, supra, 63 Cal.4th at p. 686; see 
Veamatahau, at pp. 33–34.)  Without independent admissible 
evidence of the particulars of the predicate offenses, the expert’s 
hearsay testimony cannot be used to supply them.  In the 
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
22 
absence of any additional foundation, the facts of an individual 
case are not the kind of general information on which experts 
can be said to agree.   
The Attorney General relies on the Sanchez description of 
case-specific facts as those relating to “the particular events and 
participants alleged to have been involved in the case being 
tried.”  (Sanchez, supra, 63 Cal.4th at p. 676.)  We acknowledge 
that the statutorily required predicate offenses do not fit neatly 
into the description Sanchez provided.  At least some of these 
offenses will most often have occurred before “the case being 
tried” (ibid.) and will have been committed by others who were 
not involved in the new charges at issue.  But Sanchez was 
addressing case-specific facts as they arose in the particular 
matter at hand; it did not address the question we face here.  For 
reasons already explained, we conclude that facts concerning 
particular events and participants alleged to have been involved 
in predicate offenses, too, constitute case-specific facts that must 
be proved by independently admissible evidence.   
It should be recalled that the STEP Act sought a balance 
between free association and protecting against the “clear and 
present danger” posed by this defined kind of organized criminal 
activity.  (Pen. Code, § 186.21.)  The statutory requirement that 
predicate offenses be separately proven serves to maintain that 
balance. Our interpretation here, requiring that this proof rest 
on competent evidence, also furthers that legislative intent.  In 
this respect, the proof of predicate offenses is similar to other 
kinds of case-specific facts that may have occurred before the 
commission of the charged offenses.  These kinds of facts include 
evidence of motive, prior offense evidence admissible under 
Evidence Code section 1101, subdivision (b), and prior 
convictions suffered by the defendant on trial.  It has long been 
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
23 
recognized that these kinds of facts alleged in the current trial 
must be proven by competent evidence.   
In sum, the particular facts offered to prove predicate 
offenses as required by the STEP Act are not the sort of 
background hearsay information about which an expert may 
testify.  Competent evidence of those particulars is required.17  
A gang expert may still render an opinion regarding the gang 
membership of the perpetrator of a predicate offense in response 
to a proper hypothetical question based on premises established 
by competent evidence.  (See Sanchez, supra, 63 Cal.4th at pp. 
676–677.)   
E.  The Error Was Prejudicial 
Here, Officer Calderon testified regarding the facts of 
three predicate offenses of which he had no personal knowledge.  
No independent proof of those facts was tendered by any witness 
having personal knowledge.  The People do not claim that any 
hearsay exception would support their admission.  We need not 
address what exceptions might apply or what foundations would 
be required to invoke them.  On this record, Calderon’s 
recitation of hearsay was inadmissible.   
As to the standard for evaluating prejudice, Sanchez 
observed that “improper admission of hearsay may constitute 
state law statutory error” (Sanchez, supra, 63 Cal.4th at p. 698), 
which would ordinarily be assessed under People v. Watson 
 
17  
We disapprove the following cases, which reached a 
contrary conclusion:  People v. Bermudez, supra, 45 Cal.App.5th 
at page 363; People v. Meraz (2018) 30 Cal.App.5th 768, 781–
782; People v. Blessett, supra, 22 Cal.App.5th at pages 944–945; 
People v. Vega-Robles, supra, 9 Cal.App.5th at pages 410–411; 
People v. Meraz, supra, 6 Cal.App.5th at pages 1174–1175. 
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
24 
(1956) 46 Cal.2d 818.  That test inquires whether “it is 
reasonably probable that a result more favorable to the 
appealing party would have been reached in the absence of the 
error.”  (Id. at p. 836.)  However, if the improperly admitted 
hearsay is also testimonial within the meaning of the high 
court’s confrontation clause jurisprudence (see, e.g., Crawford, 
supra, 541 U.S. at pp. 68–69), the error is assessed under the 
federal constitutional standard of Chapman v. California (1967) 
386 U.S. 18, 24, which requires any error to be harmless beyond 
a reasonable doubt.  (See Sanchez, at p. 698.)  The Attorney 
General concedes that, on this record, the Chapman standard 
applies here.  As Sanchez notes, some of the contents of police 
reports may be testimonial hearsay.  (See Sanchez, at pp. 694–
695.)   
The People argue any error was harmless beyond a 
reasonable doubt because the gang membership of those 
committing the predicate offenses was “supplied by admissible 
expert testimony.”  The People primarily point to the sequence 
of Officer Calderon’s testimony, where he first described Arvina 
13’s primary activities before giving detailed factual recitations 
of the three predicate offenses.  They argue Calderon could have 
properly opined that the predicate offenses were committed by 
gang members to benefit Arvina 13.   
This argument is flawed.  The People concede that, in 
giving his opinion, Calderon related to the jury facts he gleaned 
from inadmissible hearsay sources, including police reports, 
about which he had no personal knowledge.18  Calderon 
 
18  
Moreover, the Attorney General concedes that numerous 
hearsay statements from police reports and field identification 
 
PEOPLE v. VALENCIA 
Opinion of the Court by Corrigan, J. 
 
25 
considered this information as true and related it to the jury as 
a reliable basis for his opinion.  The jury was permitted to 
improperly rely on that hearsay to conclude the predicate 
offenses had been proven and that Valencia and Garcia acted 
with intent to benefit the gang when they committed the crimes 
with which they were charged.  Based on the extent of the 
evidence and the elements it was offered to prove, we cannot 
conclude that the error was harmless under the Chapman 
standard.19   
III.  DISPOSITION 
The judgment of the Court of Appeal is affirmed.   
 
CORRIGAN, J. 
 
We Concur: 
CANTIL-SAKAUYE, C. J. 
LIU, J. 
CUÉLLAR, J. 
KRUGER, J. 
GROBAN, J. 
JENKINS, J.
 
cards were also improperly conveyed to bolster Calderon’s 
opinion with respect to defendants’ own gang membership.   
19  
The People did not argue here or in the Court of Appeal 
that the circumstances of the charged offenses could constitute 
the necessary proof of predicate offenses.  (See People v. Zermeno 
(1999) 21 Cal.4th 927, 930–933; Loeun, supra, 17 Cal.4th at pp. 
9–13.)  We did not grant review to address such an assertion and 
express no view on that question.   
 
 
See next page for addresses and telephone numbers for counsel who 
argued in Supreme Court. 
 
Name of Opinion  People v. Valencia and People v. Garcia 
__________________________________________________________________  
 
Procedural Posture (see XX below) 
Original Appeal   
Original Proceeding   
Review Granted (published)   
Review Granted (unpublished) XX NP opns. filed 7/10/18 – 5th Dist.  
Rehearing Granted 
__________________________________________________________________  
 
Opinion No. S250218 and S250670  
Date Filed: July 1, 2021 
__________________________________________________________________  
 
Court:  Superior    
County:  Kern    
Judge:  Gary T. Friedman  
__________________________________________________________________  
 
Counsel: 
 
Elizabeth J. Smutz, under appointment by the Supreme Court,  
Michael B. McPartland, under appointment by the Court of Appeal,  
for Defendant and Appellant Edgar Isidro Garcia. 
 
Hilda Scheib, under appointment by the Supreme Court, for Defendant 
and Appellant Jose Luis Valencia.  
 
Mary K. McComb, State Public Defender, Hassan Gorguinpour, 
Deputy State Public Defender, for Office of the State Public Defender  
as Amicus Curiae on behalf of Defendants and Appellants. 
 
Kamala D. Harris and Xavier Becerra, Attorneys General, Matthew 
Rodriquez, Acting Attorney General, Gerald A. Engler and Lance E. 
Winters, Chief Assistant Attorneys General, Michael P. Farrell, 
Assistant Attorney General, Eric L. Christoffersen, Kathleen A. 
McKenna, Rebecca Whitfield, Daniel B. Bernstein, Rachelle A. 
Newcomb and Darren K. Indermill, Deputy Attorneys General, for 
Plaintiff and Respondent in No. S250670. 
 
 
 
Xavier Becerra, Attorney General, Matthew Rodriquez, Acting 
Attorney General, Gerald A. Engler and Lance E. Winters, Chief 
Assistant Attorneys General, Michael P. Farrell, Assistant Attorney 
General, Louis M. Vasquez, Daniel B. Bernstein, Rachelle A. 
Newcomb, Amanda D. Cary, Lewis A. Martinez and Darren K. 
Indermill, Deputy Attorneys General, for Plaintiff and Respondent in 
No. S250218. 
 
  
 
 
 
 
 
Counsel who argued in Supreme Court (not intended for 
publication with opinion): 
 
Darren K. Indermill 
Deputy Attorney General 
1300 I St. 
Sacramento, CA 95814 
(916) 210-7689 
 
Hilda Scheib 
P.O. Box 29098 
San Francisco, CA 94129 
(415) 750-9397 
 
Elizabeth J. Smutz 
Central California Appellate Program 
2150 River Plaza Dr., Suite 300 
Sacramento, CA 95833 
(916) 441-3792 
 
Hassan Gorguinpour 
Deputy State Public Defender 
770 L St., Suite 1000 
Sacramento, CA 95814-3362 
(916) 322-2676