CHICAGO, Ill. (WTVO) — The fatal shooting of an off-duty Illinois State trooper and a woman on Chicago’s far south side have been ruled a murder-suicide.

Antonio and Amanda Alvarez were found dead inside of a car on Monday afternoon, both with gunshot wounds to their heads. An autopsy released yesterday showed that Antonio’s wound was self-inflicted. He had been a state trooper for three years. Amanda’s death was ruled a homicide.

Police have not explained how the pair knew each other.