The suspect in the deadly shootings at the shopping complex is Patrick Crusius, 21, of Allen, Texas, three sources told CNN.

The information provided to CNN came from two federal law enforcement sources and one state government source. The federal sources told CNN that investigators are reviewing writing posted online days before the shootings that may speak to a motive.

The sources say the online posting was believed to be written by Crusius, but have that has not been confirmed.

Facebook is working with law enforcement. The Facebook and Instagram profile under the suspect's name have been removed by the company.

"Our thoughts are with the victims and their families. Content that praises, supports or represents the shooting or anyone responsible violates our Community Standards and we will continue to remove as soon as we identify it," a Facebook spokesperson told CNN.

Gomez did not identify the suspect during a news briefing, but he said a white male in his 20s was taken into custody without incident. Gomez said the man is believed to be the sole shooter. Police did not fire any shots, he said.