The Missouri Supreme Court on Tuesday granted relief  in Mark Gill v. State on the failure to adequately investigate.  [more]From the headnotes:

The circuit court clearly erred in failing to find that the performance of Gill’s counsel was deficient and that, as a result, he suffered prejudice. To prove ineffective assistance of counsel sufficient to reverse a death sentence, the movant must establish first that counsel’s performance was deficient and, second, that the deficient performance prejudiced the defense. Strickland v. Washington 466 U.S. 668, 687 (1984). While generally neither the state nor the defense may introduce evidence of the victim’s character in a murder case, the state is allowed to present evidence showing the victim’s uniqueness. If the state introduces evidence of the good character of a victim during the penalty phase, defense counsel either may object to the introduction of character evidence, which the trial court should sustain, or, as an alternate strategic maneuver, defense counsel may choose to allow the state to present the good character evidence, opening the door for defense counsel to present rebuttal character evidence.

(a) Here, the state introduced good character evidence about the victim through the testimony of the victim’s family members. Gill’s counsel should have presented rebuttal character evidence. They did not, however, because they failed to discover it. They saw the names of the sexually explicit files on the report about the computer’s contents but failed to investigate further. They had the opportunity to discover the child pornography, bestiality videos and sexually explicit instant-message conversations on the victim’s computer but failed to do so. As such, their performance was deficient, falling outside the wide range of professional, competent assistance. A reasonably competent attorney would have reviewed the report carefully and would have recognized the file names as evidence of sexually explicit material on the computer, would have conducted further investigation – including interviewing or deposing the police investigator who prepared the report about the computer’s contents and who knew the victim’s computer contained sexually explicit material – would have discovered the sexually explicit material and would have used it during the penalty phase of the trial.

(b) Had Gill’s counsel discovered the material, they could have persuaded the prosecutor to limit the family members’ testimony to victim-impact evidence rather than to elicit positive character evidence about the victim. Alternatively, had the state still chosen to elicit positive character evidence about the victim, they could have used the sexually explicit material in rebuttal, giving the jury an alternative description of the victim when it deliberated whether to recommend the death penalty. Given that the jury in the later trial of Brown – in which the defense persuaded the state not to present the positive character evidence about the victim – recommended life in prison, not death, there is a reasonable probability that the jury in Gill’s trial would not have sentenced him to death either. As such, the deficient performance of Gill’s counsel prejudiced him, and he is entitled to a new penalty-phase trial.