A recently fired employee returned to the Texas transportation company where he worked and fatally shot one person before killing himself, police said.
The gunman, whose name has not yet been released by police, was fired several weeks ago and returned to his former place of employment on May 4 armed with a pistol and a shotgun.
"Other than he was terminated, we don't know anything about him," Harris County Sheriff Ron Hickman told NBC News. "He parked right outside the building and came straight in."
The man returned to his former place of employment, Knight Transportation in Katy, Texas, at about 8:30 a.m. and started shooting immediately, according to police.
"The weapons involved was a shotgun and a pistol, but only the shotgun was used," the sheriff said.
Police found the bodies of the victim, who was reportedly a supervisor at the company, and the shooter when they arrived at the scene. They've been tight-lipped about the details as they continue their investigation.
Two other people were injured during the shooting. One was an employee of Knight Transportation who was shot once in the face with a beanbag round, a less lethal form of shotgun ammunition. The other was hit in his left arm, KTRK reports. Both people were treated at the scene.
The shooter yelled "Ya'll ruined my life" before opening fire, according to KTRK.
The shooting prompted lockdowns at nearby schools in Katy, a town of about 15,000 people some 20 miles outside of Houston.