NEW : Court papers say woman , Two kids suffered `` severe pain and anguish '' NEW : four 7-year-old girls sexually assaulted before they died , documents say . NEW : Threat of returning to prison motivated slayings , prosecutors say . Bodies found Tuesday in apartment in Oklahoma , El Reno .
NEW : Court papers say woman , four kids suffered `` severe pain and anguish '' NEW : Two 7-year-old girls sexually assaulted before they died , documents say . NEW : Threat of returning to prison motivated slayings , prosecutors say . Bodies found January 12 in apartment in El Reno , Oklahoma .