In a death penalty case, counsel rendered ineffective assistance by failing to conduct a reasonable investigation into whether there was mitigating evidence of the defendants dysfunctional childhood and background. Unlike previous cases considered by the court, counsel discovered no evidence to suggest that a mitigation case would have been counterproductive or that further investigation would have been fruitless. The failure to investigate was prejudicial, because the mitigating evidence was powerful. Defendant experienced severe privation and abuse while in the custody of his alcoholic, absentee mother, and physical and sexual abuse in foster care. This is the kind of troubled history relevant to assessing moral culpability.