CNN —Federal prosecutors charged three alleged gang members and one alleged gang associate Thursday in the fatal shooting of off-duty Los Angeles Police Department officer Fernando Arroyos during an attempted robbery. Rio’s alleged girlfriend Haylee Marie Grisham, 18, was also charged. According to the complaint, Arroyos was house-hunting on Monday with his girlfriend when a black pickup truck drove up. Rios and Cisneros pointed guns at Arroyos and his girlfriend and removed items from both, including chains from Arroyos’ neck. There was an exchange of gunfire between Arroyos and the two suspects, after which Arroyos collapsed and the two suspects fled, the release said.