In In re Cordero (1988) 46 Cal.3d 161, evidence suggested the defendant committed a charged murder while intoxicated with alcohol and PCP. Rather than pursuing this theory, however, defense counsel simply asked the defendant whether he had known what he was doing. The defendant replied affirmatively. A referee found that the attorney viewed the defendant's response to this contextually ambiguous question as " 'an unalterable fact not worth exploring further.' " ( Id. at p. 173.) Counsel failed to follow up on several leads that might have shown the defendant was intoxicated at the time of the murder. On appeal, counsel's performance in investigating the matter was found to be deficient, in that he "surrendered the cause without further inquiry" based upon the defendant's single statement that he knew what he was doing. ( Id. at pp. 182-183.) "While an attorney is not obligated to interview every prospective witness , it is patently incompetent for him to interview none regarding the crux of the anticipated defense . . . ." ( Id. at p. 184.)