Police in Los Angeles are searching for answers after a mom and her 13-year-old son were killed in their apartment.

The slain woman and her teenage son were discovered by her husband around 11 p.m. at their Van Nuys apartment when he returned home from work, the Los Angeles Times reported.

The man — who is also the boy’s father — has been cooperating with authorities and is not a suspect, officials said.

Investigators said both victims showed signs of trauma, but they’re still trying to determine how the mom and son were killed. No weapons were recovered from the scene.

“If you don’t have a witness and all you have is a bloody wound, it can be very difficult to quickly determine how the injury occurred,” LAPD Detective Meghan Aguilar told the newspaper.

Aguilar said the incident was “very unusual,” but there was no indication that the homicide was random.

“We would believe that at least the location was targeted, if not these individuals,” Aguilar told news station KTLA. “Who would target a 13-year-old though, and his mother? That’s really the question.”