Martha Marie Morrison (1956 – September 1974) was a 17-year-old American girl who was murdered in 1974. On October 12, 1974, unidentified human remains were found in Dole Valley near Vancouver, Washington. In 2015, the remains were identified by means of DNA profiling as those of Martha Morrison. Her body was found next to the remains of Carol Platt Valenzuela, who was identified shortly afterward. After Morrison's remains were identified, law enforcement encouraged the public to submit tips, as the murder was still unsolved. In August 2017, a bloodstain on a pistol owned by a longtime suspect, Warren Leslie Forrest, was matched to Morrison through DNA testing.