State police found him propped up on the side of the Pennsylvania Turnpike 44 years ago, dead - stabbed through the heart.
He was about a mile east of the Downingtown interchange in Chester County, about 30 miles Northwest of Philadelphia.
He had no identification and the only leads police had were two tattoos - a bird in flight with a heart in the background and a bulldog wearing a World War I helmet with "USMC" below it, police said.
He remained John Doe for decades, until his body was exhumed in 2009 for DNA testing.
Based on his tattoos and physical appearance at the time of his death, authorities ran the DNA samples and description through the Naval Criminal Investigative Service Cold Case Unit and the Marine Corps Absentee Collection Unit.
In May, the DNA testing revealed his name: Cpl. Robert Daniel Corriveau.
State police are looking for anyone who may have served with Cpl. Corriveau or were patients with him at Philadelphia Naval Hospital in October and November 1968.
Marine Cpl. Corriveau, then 20 years old, was wounded on three separate occasions while serving in Vietnam in 1967. He was being treated in the psychiatric unit at the Philadelphia Naval Hospital for a combat-related condition when he disappeared. He was found dead Nov. 18, 1968.
The Lawrence, Mass., native was no stranger to mental health treatment.
He received psychiatric treatment at Chelsea Naval Hospital after he in enlisted in the Marine Corps in 1965, and served multiple tours of duty in Vietnam, where he received two Purple Hearts.
Anyone with information is asked to contact state police at 610-268-5158 or email RA-1968MarineDeath@pa.gov, People can also call Pennsylvania Crime Stoppers toll free at 800-4PA-TIPS or visit www.pacrimestoppers.org.
Contact the writer: ksullivan@timesshamrock.com, @ksullivanTT on Twitter