DALLAS (AP) — The FBI received a call about three years ago about the U.S. Army veteran who opened fire on a courthouse in downtown Dallas, a federal law enforcement official said Thursday.

Brian Isaack Clyde was shot and killed Monday by security officers after he began shooting at the Earle Cabell Federal Building. The 22-year-old was armed with a high-powered rifle and more than 150 rounds of ammunition, but there were no other serious injuries or deaths.

The FBI did not investigate Clyde after the July 1, 2016 call because it did not contain a specific threat, according to the official, who spoke on condition of anonymity because the shooting probe is ongoing. The official said a member of Clyde’s family called a national tip line to say Clyde was suicidal and had a fascination with guns.

Clyde’s mother, Nubia Brede Solis, told The Dallas Morning News that her son’s half-brother had called the FBI with concerns.

The call came while Clyde was enlisted. He served as an infantryman from August 2015 to February 2017 but was never deployed to a war zone, according to the Army.

The FBI said Clyde was honorably discharged, but his short period of service suggests he left the military earlier than planned.

The Army has declined to say why Clyde was discharged, citing privacy laws.

(Copyright: the Associated Press)