Police in Northern California say they are looking for the mother of a 4-year-old girl who was found dead in her bed by officers conducting a welfare check.

The Napa Police Department said they have not been able to find 23-year-old Sara Krueger and her boyfriend, 26-year-old Scott Warner, since the body of Krueger's daughter was discovered on Saturday afternoon.

Police say neighbors reported seeing the couple carrying luggage away from the apartment complex where Krueger and the girl lived earlier Saturday.

The department said investigators suspect foul play in the death of the girl, whom they did not identify. No details about how she died have been disclosed.

Elizabeth Cherchourka, who manages the apartment complex, told Oakland television station KTVU that she often saw the girl riding a bicycle around the complex and that she appeared well cared-for.