The Metropolitan Police Department arrested two suspects in the ambush shooting of a U.S. Park Police officer who was hurt while driving in an unmarked vehicle in Washington, D.C., authorities said Tuesday.

In announcing the arrests, police said Darren Foster, 21, and Asheile Foster, 22, were charged with assault on a federal police officer (gun), after a shooting Monday evening near the District’s border with Maryland. Authorities said the officer was conducting an investigation at the time.

U.S. Park Police Chief Scott Brecht said during a press briefing that the officer was working on an investigation when two gunmen fired multiple times as he drove by. Brecht also said the attack occurred while the officer was in the area.

Metropolitan Police said the officer was investigating an incident in the Park Police’s jurisdiction when he was shot. Police said the officer drove away to escape the gunfire and was later medevacked to a local hospital.

A law enforcement official told The Associated Press that the officer was shot in the shoulder. The officer was released from the hospital Tuesday, police said.

Jeffery Carroll, Washington’s interim police chief, said at a press briefing Monday that the officer was targeted and that it was possible the gunmen knew he was a police officer.

Authorities said federal officials assisted in the investigation as the case moved from the shooting on Monday into arrests and charges announced Tuesday.