Cook v. Warden, Georgia Diagnostic Prison, 677 F.3d 1133

Petitioner Andrew Cook convicted in Georgia of two counts of malice murder and two counts of felony murder, with a death sentence for one killing and life imprisonment for the other.
Trial counsel chose not to present mental health mitigation evidence due to potentially damaging counter-evidence.
River Edge behavioral health records, showing major depression with psychotic features, were not disclosed to petitioner's psychologist and were argued to have limited impact on outcome.
Counsel investigated upbringing and presented family testimony; other potential witnesses were deemed irrelevant or potentially harmful.
Counsel prepared and elicited substantial testimony from petitioner's father, John Cook, who testified as a pivotal witness during sentencing.
Petitioner confessed to his father (an FBI agent) in a private setting; the confession occurred before or without custodial interrogation by state agents, and it was not obtained through coercive government interrogation.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Ineffective assistance for mental health mitigation	Cook argues counsel failed to investigate/present mental health evidence.	Georgia Supreme Court found no deficient performance or prejudice given the evidence.	No Strickland deficiency or prejudice established.
River Edge records as mitigation material	River Edge records would plausibly change sentencing outcome.	Reviewing court found no reasonable probability of different outcome; records would not have altered verdict.	No prejudice under Strickland; no unreasonable factual determination.
Upbringing mitigation investigation/presentation	Counsel failed to investigate/present upbringing mitigating evidence.	Counsel adequately investigated and presented upbringing; additional evidence would be harmful or cumulative.	No deficient performance or prejudice.
Preparation of key witness John Cook	Counsel inadequately prepared John's testimony.	Counsel engaged with John Cook; testimony was effective and consistent with mitigation goals.	No deficient performance or prejudice.
Admissibility of confession to father (Miranda)	Confession to father occurred without Miranda warnings and implicates custodial interrogation.	No Miranda violation; father was acting as a father, not as government agent; no custodial interrogation.	No Miranda violation; admissible under applicable precedent.

Strickland v. Washington, 466 U.S. 668 (1984) (establishes deficient performance and prejudice standard for ineffective assistance)
Waters v. Thomas, 46 F.3d 1506 (11th Cir. 1995) (deference to strategic decisions in witness selection and timing)
Wiggins v. Smith, 539 U.S. 510 (2003) (reweighing aggravating and mitigating evidence for prejudice)
Wong v. Belmontes, 130 S. Ct. 383 (2009) (requires consideration of totality of mitigating evidence)
Porter v. McCollum, 130 S. Ct. 447 (2009) (mitigation evidence strength differs case-to-case)
Williams v. Taylor, 529 U.S. 362 (2000) (limits per se rules; factors in mitigation investigation)
United States v. Gaddy, 894 F.2d 1307 (11th Cir. 1990) (Miranda for statements to a non-governmental source with familial context)
Miranda v. Arizona, 384 U.S. 436 (1966) (establishes custodial interrogation safeguards)