An 18-month-old girl has died after being found submerged in a bathtub in a St. Paul foster home.

Police say the girl was pronounced dead on Thursday, a day after she was found in the tub with a 3-year-old sibling. The girl's body was turned over to a medical examiner on Saturday for an autopsy.

Police are investigating the circumstances of the incident, which they say happened while the foster father stepped out of the room for a moment. Investigators are trying to determine how long the children were left unattended.

St. Paul Police Sgt. Paul Schnell says criminal charges are possible.