(AP) -- Authorities are searching a central New York property for evidence in the disappearance and presumed slaying of a college student 35 years ago.

Trooper Jack Keller of the New York State Police confirmed to the Observer-Dispatch of Utica on Monday that FBI agents and local law enforcement investigators were digging in the Madison County town of Sullivan for clues to the death of Tammy Mahoney.

The 19-year-old city of Oneida resident was last seen in early May 1981 as she hitchhiked along Route 46. Police have said they believe she was on nearby Oneida Indian Nation territory when she was raped and murdered.

Mahoney was attending the state college in Morrisville in Madison County when she disappeared while hitchhiking to see friends in nearby Hamilton.