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.

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

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