In In re Sassounian (1995) 9 Cal.4th 535, the court examined the failure to disclose impeachment evidence--promises of benefits in exchange for testimony (id. at p. 542)--as to the credibility of a jailhouse informant (Busch) who claimed the defendant confessed to the crime and to its national-origin motivations. (Id. at pp. 539-540.) Sassounian concluded the nondisclosure was harmless in part because the undisclosed information merely involved additional impeachment for a witness who had already been so "extensively impeached" that "the 'testimonial thread' that he plied was already severely 'tattered' " that it was "hard to assign a weight" to the impact Busch's testimony actually had on the critical issues. (Id. at pp. 548, 547.) More importantly, Sassounian stated that "separate and apart from Busch's testimony, . . . there was overwhelming evidence relating to the crime" (id. at p. 548) and "even without Busch's testimony, the overwhelming evidence supports only one reasonable inference as to the national-origin special circumstance," and ultimately concluded that "in a word, 'there was nothing "close" about this' issue." (Id. at pp. 549, 548.)