In People v. Sanchez, S216681, the California Supreme Court today built on recent precedent from the U.S. Supreme Court and a tide of judicial and scholarly criticism to find case-specific "statements" related by a prosecution "gang expert" not only constituted inadmissible hearsay under California law, but also were "testimonial" so should have been excluded under Crawford v. Washington. I generally steer away from substantive legal discussions in this space but, since this was my case, I will diverge from that precedent a bit. Sanchez considered the widespread use of "gang expert" testimony in criminal prosecutions to prove an offense was "gang related," so as to increase the sentence. Generally, an officer or detective with some familiarity with a gang will testify as to the gang's history, activities, common symbols, etc. and then ultimately opine the offense was gang-related. The problem comes from the conflict between the old adage that an expert can rely on hearsay and the defendant's 6th Amendment right to confront and cross-examine the witnesses against him because, often, the "gang expert" will rifle through the files at the police department and find various documents and records which were created by other officers, but who are not called to testify. Hence, the defendant cannot cross-examine the "real" witness against him. Justice Corrigan's unanimous opinion explains why an "expert" cannot present "case specific" facts concerning which the expert has no personal knowledge, so those facts must be presented by witnesses who do have personal knowledge and can be cross-examined. Stylistically, the opinion is well-written, including various common-sense examples to illustrate its points. It is recommended reading for practitioners, law students struggling through evidence class, and the public. It also demonstrates, as did the late Justice Scalia's opinions in this area, that the 6th Amendment is a unique corner of jurisprudence where justices labeled as "conservative," "moderate" or "liberal" can find common ground. read the opinion: http://www.courts.ca.gov/opinions/documents/S216681.PDF