Arizona authorities are investigating after a fetus was found in a pipe at a wastewater treatment plant.

Santa Cruz County Sheriff Tony Estrada says employees at Nogales International Wastewater treatment Plant in Rio Rico reported finding the fetus on Friday afternoon.

The plant is about 9 miles north of the Arizona-Mexico border. Estrada says the fetus came through a pipe from Mexico, although it's unclear whether it entered the system in Mexico or in Arizona.

Estrada says the Office of the Medical Examiner in Tucson says the fetus was female and had developed for about 17 weeks. He says the umbilical cord was still attached and there didn't appear to be any signs of trauma.

He says the medical examiner's office is trying to determine where it came from.