The 22-year-old mom was reported missing by her father on March 23, 1984, troopers say. She had been living on East 8th Street in Northampton Borough with her husband James and their 5-year-old son.
After her dad reported her disappearance, James told investigators that his wife had chosen to leave their home that February. His story was later contradicted by physical evidence and he was eventually convicted of killing her in 2001, state police say.
He was sentenced to life in prison, according to troopers.
Kelly's remains were never located and anyone who may have information is asked to call Pennsylvania Crime Stoppers at 1-800-472-8477 or submit an anonymous tip online.
Click here to follow Daily Voice West Chester and receive free news updates.