And a dramatic scene unfolding in Omaha where an explosion at a factory left two workers dead, several others right now are fighting for their lives. ABC's Clayton Sandell is learning new details about the plant's history. Reporter: This morning, this Omaha manufacturing plant is a twisted dangerously unstable wreck. 50 firefighters called Monday to reports of an explosion and collapse. Just heard a crack, pop and big ball of fire. Reporter: Carrie cook's fist sent a message. It said major accident. Love you. Reporter: Cook's fiance was rescued along with nine others. He's okay. Four others critically injured. Overnight they identified one of the employees killed, 53-year-old Keith evert. The plant's owner, international nutrition, was hit with half a dozen serious violations in 2012 including problems with wiring and safety equipment. Overnight the company said it could not comment on those violations or Monday's incident. Investigators say they still don't know exactly what happened and are now trying to solve a deadly mystery. For "Good morning America," Clayton Sandell, ABC news, Denver.