PRONE investigation has found plenty of other deaths that deserve additional scrutiny. Two cities – Denver and Minneapolis – have decided not to wait for potential legislation on prolonged prone restraint. After the first part of PRONE aired in both cities, the two police departments elected to change the way they train their officers. I NTERACTIVE GRAPHIC: "It’s difficult to watch officers continue to make the same mistake" The warning arrived in the email inboxes of all badged members of the Denver Sheriff Department on Nov. 2, 2015. “Once a subject has been restrained, immediately place him/her into a recovery position (lying on his/her side or seated upright,” the training bulletin said.