The suspect died in a car crash seven years ago.
Police say a witness who was afraid to come forward years ago told investigators recently that a 17-year-old runaway confessed to the murder a year after it happened.
Dennis Piernick was found dead of stab wounds at his Salt Lake City apartment May 16, 1982.
Police say the purported confession - along with a backpack, clothing and a pack of cigarettes left at the scene - ties Rodney Van Komen to the crime.
Van Komen, however, died in a car crash in 2005.
Police say VanKomen was a runaway who frequently stayed with a friend at Piernick's apartment complex.
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