An off-duty Houston police sergeant shot and killed a robbery and assault suspect on a city bus Tuesday.

Police Chief Art Acevedo said the suspect had beaten the female guard at a nearby nightclub and taken her pistol, ABC13 reports.

Acevedo said the suspect ran toward the transit center and the guard ran after him.

She flagged down the officer for help.

The chief said the officer, who was heading home at the time, confronted the suspect who had gotten on a bus.

The officer demanded the suspect drop the weapon. He opened fire after the man did not comply, Acevedo said.