Story highlights

Former co-worker says killer was an angry, violent bigot

Ex-wife says suspect Omar Mateen abused her, held her hostage from family

CNN  — 

As the world mourns the 49 victims of the Orlando nightclub massacre, investigators are working to piece together a picture of the man responsible for the deadliest mass shooting in U.S. history.

What could have driven Omar Mir Seddique Mateen, a New York-born security guard who was the son o