VIRGINIA BEACH, Va. (AP) — The post office where survivors reunited after a mass shooting in a Virginia Beach government office building now is named after the man who gave his own life for his co-workers.

A plaque was unveiled Friday honoring Ryan Keith Cox at the post office that now bears his name, The Virginian-Pilot reported. Cox was one of 12 people who died in the mass shooting last May 31 at the Virginia Beach Municipal Center.

“We are a city of heroes, and Keith is a perfect example of one of them,” Mayor Bobby Dyer said during the ceremony.

In interviews, Cox’s co-workers have said he ushered women into a room and told them to barricade the door. Cox then left to see if anyone else needed help. The gunman and shot and killed him soon after that.

Cox, 50, had been an account clerk in Virginia Beach’s public utilities department for 12 years.

In August, President Donald Trump approved renaming the post office, where city workers were first led by police after the shooting.

Cox’s father, E. Ray Cox, told the gathering of more than 100 people that his son had been a friend to the shooter and counseled him through tough times.

“For some reason, one day, he decided that the only way to deal with his problems was not to have counsel or to talk, but to go home, get a gun and come back and start shooting people,” he said. “And the very one who had been so close at his side, who had been so busy trying to help him to get his life in line, he then carelessly took his life.”

DeWayne Craddock, the shooter, had been an engineer with the city’s public utilities department. He died in a gunbattle with police.

A months long independent probe into the shooting ended in November, but it provided no clear answers as to why Craddock had opened fire. It also found no warning signs by the shooter that could have prevented the tragedy.