When a prosecutor asks for an expert's opinion in a criminal case, can the prosecutor ask for a hypothetical question?

Here, Detective Shear was most assuredly familiar with the facts of the particular case being tried based on his own thorough investigation. Where most, even if not all, of the evidence upon which an expert's opinion is based is within that witness's personal knowledge and has already been the subject of his testimony, it seems a pointless exercise to require the prosecutor to summarize that evidence in the form of a hypothetical question before asking for the expert's opinion.⁵ On this record, and without generalizing to other situations not before us, I am not prepared to hold Detective Shear's testimony exceeded the scope of a permissible expert opinion. (See generally People v. Vang, supra, 52 Cal.4th at p. 1048, fn. 4 ["[i]t appears that in some circumstances, expert testimony regarding the specific defendants might be proper"].)