Two people were killed and two more seriously injured in a shooting in Seattle, Washington on Wednesday.

The unidentified gunman shot a female motorist, injuring her, then walked into the street and shot at a nearby bus. The driver was injured but no one inside the bus was harmed.

The gunman then shot a nearby driver, killing him, and stole the man’s car to drive it into another nearby car, killing that driver.

The suspect is in police custody but the motive behind the act is unclear. Deputy Police Chief Marc Garth Green said in a press conference the shootings were a “random, senseless act”, as per a report by the Seattle Times.

The suspect was later taken into police custody and is being treated for non-life-threatening injuries.