LOS ANGELES (AP) — Four people have been arrested after in the investigation into the fatal shooting of an off-duty Los Angeles police officer.

The Los Angeles County Sheriff’s Department announced the arrests Wednesday in a brief statement that gave no details.

Officer Fernando Arroyos was shot Monday night in an unincorporated area of south Los Angeles County. Authorities have said the 27-year-old Arroyos was shopping for a house with his girlfriend. A pickup truck approached, several suspects got out, there was an argument and gunfire was exchanged between the assailants and the officer.

The girlfriend was not wounded.