An autopsy is underway on a 13-year-old girl found dead near a Pennsylvania river days after she walked to a dollar store to buy a coloring book and never returned.

State police say the autopsy is being conducted Monday on Shevy McGiffin, whose body was found Sunday near the Clarion River, about 65 miles northeast of Pittsburgh.

Police had been searching for the girl since she left her Clarion home to go to Dollar General on Friday. The store was less than a five-minute walk from her home.

Her mother tells WPXI-TV (http://bit.ly/2czfOJG ) she believes the girl had been abducted.

State police say the case remains under investigation.

No other information has been released.