NAPA (AP) — A Northern California woman wanted for questioning in the death of her 3-year-old daughter was detained along with her boyfriend Sunday at a San Francisco Bay Area commuter train station and turned over to authorities who are investigating the child’s death as a homicide, police said.

Sara Krueger, 23, and her boyfriend, Scott Warner, 26, were arrested without incident at a Bay Area Rapid Transit station in the city of El Cerrito after police there alerted BART officers to be on the lookout for the pair, Lt. Gil Lopez said.

Detectives from the Napa Police Department had been trying to locate the couple since Krueger’s daughter was found dead in her bed by officers conducting a child welfare check on Saturday afternoon.

The child, whom police have not yet named, showed signs of having been sexually assaulted and blunt force trauma, Napa police Lt. Debbie Peecock said.

Before the two were taken into custody, they last were seen carrying luggage from the Napa apartment where Krueger and the girl lived, Peecock said. A tip from a private citizen led to their being stopped about 30 miles away in El Cerrito, she said.

They have been brought back to Napa and were being interviewed on Sunday afternoon, she said.