Authorities say a woman and a 4-year-old girl were found shot to death on the side of a highway in the Mississippi Delta.

Bolivar County Deputy Coroner Murray Roark says a FedEx driver found the bodies next to a pickup truck on U.S. Highway 61 just north of the tiny town of Duncan about 5:30 a.m. Tuesday

Roark told The Associated Press he believes the 44-year-old woman is the child's mother, but isn't positive. Both were shot once in the head. Their identities were being withheld.

Roark says law enforcement agencies were searching for the woman's boyfriend. He says the bodies were sent to Jackson for an autopsy.

A message left at the Bolivar County Sheriff's office was not immediately returned.