In an interrogation that stretched 12 hours, the man confessed to the murder and supplied chilling details of the crime. Stepping before jurors in an upstate New York courtroom, prosecutors pointed to those admissions as damning proof of guilt, dismissing the defendant’s history of mental illness. There was one problem: The man convicted in that trial, Douglas Warney, was innocent, the confession a product of his own mental instability and interrogators’ apparent zeal. Now, nine years after Warney was …