The FBI is offering a new $20,000 reward in the case of Farmingdale teenager who disappeared nearly four decades ago in upstate New York.

Officials say Tammy Mahoney, 19, was last seen hitchhiking on state Route 46 in Oneida on May 8, 1981. Authorities believe Mahoney, a Morrisville College student, was raped and killed after attending a party on Oneida national tribal land.

Her body was never recovered. The Oneida Nation said it would match the FBI's reward with an additional $20,000.

Mahoney's sister, Marlene Laccesaglia, says she's begging anyone with information to come forward to help finally bring peace to her heartbroken family.

Mahoney graduated from Farmingdale Senior High School in 1979 before heading to college. Her classmates remember that she loved animals and dreamed of becoming a veterinarian.

Mahoney's classmate, Mike Grello, started a Facebook page named Justice for Tammy Mahoney and hopes the $40,000 reward will bring justice.

Officials ask anyone with information to call the FBI's Utica office at 315-731-1781.