Most Violent Jail Inmates | A Hidden America: Inside Rikers Island PART 1/2 ABC News Published on May 21, 2016 ............................................ Diane Sawyer went inside the unit called punitive segregation, where inmates are locked up for up to 23 hours a day. WATCH THE FULL EPISODE OF NIGHTLINE: https://abc.tv/2t61P30 5/20/16 - A Hidden America: Inside Rikers Island .................................... Category News & Politics