In re Welch, 61 Cal. 4th 489

In 1989 Welch was convicted of six counts of first-degree murder, multiple special-circumstance found true, and sentenced to death; the conviction and sentence were affirmed on direct appeal.
In a habeas petition filed in 2002 Welch alleged (1) juror misconduct from improper bailiff communications and (2) ineffective assistance of counsel at the penalty phase for failing to investigate/introduce evidence of serious childhood abuse.
The Supreme Court issued an order to show cause limited to those two claims and referred the matter for an evidentiary hearing before a referee, who conducted extensive testimony and issued findings.
The referee found no credible evidence that bailiffs communicated prejudicial information to jurors but concluded trial counsel’s mitigation investigation was inadequate for failing to locate and interview several available family witnesses about childhood abuse.
The referee further found that additional social-history witnesses and expert testimony would have strengthened the record of abuse and could have altered expert diagnosis, but identified strong aggravating evidence and plausible prosecution rebuttal.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Juror misconduct—bailiff communications (urine in stairwell; witness threats)	Bailiff(s) told jurors Welch urinated in stairwell and communicated threats by Welch/supporters, prejudicing the jury	Bailiffs did not communicate such facts to jurors; jurors’ impressions explained by testimony at trial and posttrial prosecutor remarks	No credible evidence of improper bailiff communications; claim denied
Ineffective assistance at penalty phase—failure to investigate/introduce child‑abuse mitigation	Counsel failed to contact available family/social‑history witnesses (aunt, uncle, sister); their testimony and resulting expert support would have meaningfully bolstered mitigation	Counsel reasonably relied on records and unavailable/uncooperative family; even if additional evidence existed prosecution rebuttal and overwhelming aggravators made a different sentence unlikely	Court assumed possible deficient performance but found no prejudice: additional evidence would not have created a reasonable probability of a different penalty verdict

Strickland v. Washington, 466 U.S. 668 (establishes deficient-performance and prejudice test for ineffective assistance)
Wiggins v. Smith, 539 U.S. 510 (counsel’s failure to investigate social history can be deficient and prejudicial in capital cases)
Williams v. Taylor, 529 U.S. 362 (extensive childhood-abuse mitigation may undermine confidence in death sentence)
Rompilla v. Beard, 545 U.S. 374 (failure to uncover and present substantial mitigating background evidence prejudicial)
In re Hamilton, 20 Cal.4th 273 (extraneous communications to jurors raise rebuttable presumption of prejudice)
In re Carpenter, 9 Cal.4th 634 (tests for prejudice from external juror communications)
In re Crew, 52 Cal.4th 126 (evaluating causal connection between family history and capital crime for mitigation)
In re Visciotti, 14 Cal.4th 325 (considerations in assessing mitigation and prejudice)