CHICAGO (AP) — Chicago Police say they are investigating the death of a 5-month-old boy who drowned in a bathtub when his mother fell asleep while giving him a bath.

The Chicago Tribune reports that the mother was giving her son a bath at about 10 p.m. on Friday in her home in the Stony Island Park neighborhood on the city's South Side when she fell asleep. Police say that the mother told officers that when she woke up about an hour later, the baby was underwater.

The child was pronounced dead at Advocate Trinity Hospital. Police said Saturday morning that the child's death remains under investigation and that the mother has not been charged with a crime.