San Francisco Police Officer Chris Samayoa has been fired for shooting a carjacking suspect last year. He was four days on the job working with a training officer at the time of the Dec. 1 shooting.

Police Chief Bill Scott fired the officer for killing 42-year-old Keita O’Neil, sparking outrage from the city’s police union and its president, Marty Halloran.

“Chris was fired for doing what he was trained to do by the SFPD Academy, and for what happened on his fourth day on the job under extremely stressful and difficult circumstances,” Halloran wrote in a statement. “This was a needless action as any taken by someone wearing the uniform of our chief.”

On Dec. 1, O’Neil allegedly assaulted a state lottery worker in the Potrero Hill neighborhood and stole her minivan before leading police on a winding chase through the Alice Griffith public housing complex in the city’s Bayview neighborhood.

After the brief pursuit with police, O’Neil abandoned the stolen vehicle and started running toward the patrol car occupied by Samayoa and his training officer.

Samayoa’s body camera footage shows the officer drawing his pistol while sitting in the passenger seat of a still moving patrol vehicle. The video then shows him open the side door and fire a single shot.

The shooting remains under investigation by the department’s internal affairs division, the homicide bureau and the San Francisco district attorney’s office, SF Gate reports.