The 25-year-old was found dead of multiple gunshot wounds on the north shoulder of Interstate 276 in Upper Southampton on July 15, 1976, state police detectives say.
During the initial investigation, police learned that Schonleber "was involved in criminal activity" with various "associates" in New Jersey and greater Philadelphia, troopers said.
At the time he died, police said the 25-year-old was wanted in the Garden State for busting out of a Bordentown prison in December of 1975. Citing a contemporaneous newspaper report, troopers said he was "serving a five-year sentence for possession of dangerous drugs."
Schonleber was known to go by several aliases, including David Gibson, Todd Lambert, Terrence Sori, and Terrance Bori.
Information that leads to a break in the case may result in a cash reward. To submit a tip, call Pennsylvania State Police at 610-861-2026 or visit the Pennslyvania Crime Stoppers webpage.
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