One of the gunmen behind the shooting at a Texas cartoon contest that featured images of Prophet Muhammad strongly hinted on Twitter that he was about to get violent about 20 minutes before opening fire, the Chicago Tribune reports.
“May Allah accept us as mujahideen,” or holy warriors, he tweeted.
One of his hashtags read: “#texasattack.”
Federal authorities were tracking 31-year-old Elton Simpson’s Twitter account and even had an open investigation on him at the time.
Homeland Security and the FBI also issued bulletins to local law enforcement, warning that the cartoon contest in Garland was a possible terrorism target.
Simpson and his roommate, Nadir Soofi, were killed, but not before shooting a security guard in the leg.