Karen Read, accused of murdering her boyfriend, Boston police officer John O'Keefe, will feature in an exclusive interview on ABC’s '20/20' on Friday. Read, who is charged with second-degree murder, claims she is innocent and alleges a law-enforcement cover-up. She describes finding O'Keefe's body in the snow, contradicting prosecutors who argue she hit and left him to die in a blizzard. Her first trial ended in a mistrial, and a retrial is scheduled for January. The interview will air at 9 p.m. and be available on Hulu.