CHICAGO (CBS) -- A 4-year-old Rock Island girl who was the subject of an Amber Alert earlier this month was never abducted, and was safe at home the entire time, police said.

Two girls who authorities say were abducted by their father after he allegedly killed their mother, were found safe and the suspect taken into custody.

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.