About noon Sunday, a San Antonio police officer was shot and killed while performing a routine traffic stop near police headquarters downtown, police Chief William McManus said.

McManus said the shooting occurred on the south side of SAPD headquarters, where an officer was issuing a traffic citation. As he did so, a black vehicle pulled up behind the officer’s unit.

The suspect got out of the car, walked up to the passenger window and fired one round into the patrol car, hitting the officer in the head, McManus said. He said the suspect reached in and fired again, hitting the officer a second time.

The suspect then drove off, McManus said during a news conference.

The suspect is described as a black male, 5′ 7″to 6-foot tall, wearing a gray shirt and black pants.

According to chatter on police scanners, police were searching the area near headquarters and the surrounding buildings for the shooter, while homicide detectives were interviewing witnesses who were either near a VIA bus stop, or on a VIA bus near where the shooting occurred.

“Right now we are looking for a possible motive,” McManus said. “We are looking for video footage that may help us identity this individual.”

The officer was a 20-year veteran of the force, but no other details were given.

“It’s always difficult, especially in this day and age, where police are being targeted across the country,” McManus said.

He said this is everyone’s worst nightmare, from the officers on the department, to officer families, to those who support the police department.

In a news release, Mayor Ivy Taylor said this type of crime cannot and will not be tolerated. She gave her condolences to the family of the officer and to the entire police force.

Governor Greg Abbott also condemned the killing and said attacks on law enforcement cannot be tolerated and must be met with swift justice. He asked all Texans to join together in prayer for the officer’s family.

Outgoing Bexar County Sheriff Susan Pamerleau said county deputies are actively looking for the suspect and assisting SAPD in any way they may need.