“The Court: Counsel, that’s irrelevant at this stage. He didn’t do it.”
When Maple tried to explain the question’s relevance, the court twice cut him off, saying, “Your next question.”
According to defendant, the court’s ruling “prevented the jury from fully evaluating the witness’s overall expertise and his familiarity with the particular testing equipment which he used.” Schliebe, however, was extensively cross-examined on those topics both before and after the complained-of ruling. Defendant was not constitutionally entitled to ask the expert how a test the expert did not do would have been done had he done it; even the expert’s confession of ignorance as to how such a test is done would not have discredited his data and conclusions as to the analyses he did perform. (See People v. Bell (1989) 49 Cal.3d 502, 531-532 [expert may be cross-examined on the reasons for his opinion, and on certain relevant material that the expert failed to consider in reaching his opinion, but not on matters irrelevant to the import or credibility of his opinion].)
Second, defendant complains that the court interfered with counsel’s effort to cross-examine Schliebe about his failure to account for the Bremstrahlung effect in certain of his analyses. These parts of the cross-examination are very difficult to understand, partly because counsel himself confused the exhibits with one another, partly because counsel and the witness both sometimes referred to exhibits as “this” or “that” rather than by number or by reference to the source of the paint samples analyzed, but mainly because counsel mixed inquiries about the Bremstrahlung effect with inquiries about apparent quantity differences in individual elements, such as zinc and iron, in the samples; as a consequence, the general subject of the examination became uncertain, and it was unclear which of counsel’s technical questions were foundational and which called for conclusions.