John Doe #83 is the designation for an unidentified man who was found dead on the balcony of room 16 of the Gateway Motel in Prophecy Creek, Pennsylvania on 3 April 1983. He was initially known as "John Doe #83-1," but the suffix was dropped when no other unidentified bodies were discovered during that year.

The man's death was investigated by newly-promoted Prophecy Creek Police Department Detective Lysander Michener, who found a business card in the man's jacket pocket from the Wenro County Credit Union with a Xi symbol sketched on the front and a line of poetry hand-written across the back reading: "Upon that timeless island's bloody sand...four brothers stand."