Not simply because the expert relied on a report. A gang expert may explain relevant background and personal observations, but repeating a case-specific statement to the jury as true can raise a hearsay objection. The statement’s truth-use and any confrontation issue must be analyzed separately.

Separate the expert’s opinion from the underlying statement

Evidence Code section 801 allows an expert to rely on matter experts in the field reasonably use. That does not automatically make the underlying statement admissible for its truth. Under section 802, an expert may explain the reasons for an opinion, subject to other evidence rules, and the court can examine the basis.

In People v. Sanchez, the California Supreme Court distinguished general background, an expert’s own observations, and properly supported hypotheticals from case-specific out-of-court facts repeated as true. For each statement, ask who made it, when and why, whether the expert is offering it for its truth, and whether it is independently admissible or supported by a hearsay exception. A police report or field-interview card is not automatically admissible just because it appears in the expert’s materials.

Treat confrontation as a separate question

If a case-specific statement is testimonial, the prosecution generally must show the declarant is unavailable and the defendant had a prior opportunity to cross-examine, absent forfeiture by wrongdoing. A statement can present a state hearsay problem even when it is not testimonial. Conversely, not every statement in a police record is testimonial; purpose and circumstances matter.

The practical review is statement by statement: compare the expert’s report and proposed testimony with the underlying report, field card, STEP notice, or other source. Identify any independent witness or admissible record that could establish the same fact. Then make a timely, specific objection to the particular statement and preserve the court’s ruling and the proposed alternative, such as a hypothetical that does not assume disputed facts.

People v. Perez addressed a trial held before Sanchez and does not excuse failing to object in a current trial. A challenge to an expert’s basis does not automatically exclude the opinion or defeat a gang allegation; it depends on the statements, their use, and the evidentiary record.

For general information about California gang allegations, see the firm’s gang-enhancement defense page. The Law Offices of David S. Chesley represents people facing California criminal allegations, including gang enhancements. To discuss the reports and proposed testimony, call (800) 755-5174.