Detectives located the suspect and the children by tracking signals from both his cellphone and his slain girlfriend’s, which had gone missing, Kings County Sheriff David Robinson told reporters at a news conference on Thursday.

The Amber Alert included Los Angeles, Orange, San Diego and Riverside counties, with authorities saying the suspect may have fled to Mexico.

Authorities searching for a man suspected of killing a woman and abducting their two young daughters issued an Amber Alert in the case Wednesday.