Jason King was a young man accused of raping and murdering Jennifer Durning, a Canadian student who went missing during her class field trip to New York. King revealed that he had consensual sex with Jennifer and then, his cousin Nicky Pratt and their friend Doug Waverly raped her and later murdered her.
After Jason testified against his cousin to the grand jury, his parents took him out of town to get away until he was needed for trial. Later, Jason went missing, and when the detectives were unable to locate him in time, the charges against Nicky and Doug were dismissed with prejudice.
In the end, Jason was discovered to have been kidnapped and murdered by Nick and Doug, with the assistance of Nick's girlfriend, court officer Emily McCooper. His body was dumped in the river by Nick and Doug in the same place they dumped Jennifer's. Unlike hers though, his body got caught on a bridge, thus allowing Nick and Doug to be charged with his murder. (SVU: "Gone")