A body found in a trash barrel was that of a 6-week-old Illinois girl, and authorities questioned the parents who had told them the baby was abducted much like another infant daughter three years ago.

An autopsy performed Thursday confirmed the identity of Heather Sims, who was reported abducted last weekend under circumstances that mirrored the 1986 disappearance of her sister.The first infant, 13 days old, also was found dead.

Several hours after the autopsy, authorities broke windows to get into the Sims home right across the river from this Mississippi River town.

Robert and Paula Sims were not at their home in Alton, Ill., but went to the Alton police station to answer questions later Thursday, said Sgt. Rick McCain.

Police refused to say what they were looking for at the home.

Dr. Mary Case, the St. Charles County medical examiner, would not comment on Heather's cause of death but said it was a homicide.

A fisherman found the baby's body Wednesday night. He searched the barrel and found the body in a plastic bag.