The tragic teen that struck a chord with millions was named as Jason Callaghan on Wednesday (December 9).
The 19-year-old's case puzzled investigators for two decades after he was found in a car that had hurtled off a US motorway after a Grateful Dead gig — killing driver Michael Hager and his mystery passenger.
Jason's injuries were so severe officials could not figure out who he was.
But in an incredible case of crowd-sourced detective work, social media users figured out just who the teen was.
The online manhunt began after the infamous case struck a chord with crime fanatic Lauren Rutley 10 years ago.
“It just broke my heart…that he was so young, and no one had reported him missing at the time,” said Mrs Rutley, who helped publicise the case online.
Mrs Rutley has been cross referencing missing person reports against "Grateful Doe" clues and posting them on cold-case online forums since 2005.
But it was not until Reddit – a site where users can post links to viral videos and pictures – caught wind of the mystery last year that the case took off.
Computer-generated images that mocked up what the victim may have looked like before the crash were posted on the site and viewed by over half a million people.
Within months two men claimed to have known Doe and that he was a young man from Mrytle Beach in South Carolina, US.
Armed with the new information, volunteers blitzed social media and local newspapers with the story.
Jason had never been reported as missing despite the fact that no-one had seen him for 20 years.
But his family saw the reports on Facebook this year and alerted the authorities.
After submitting DNA to the police they were told this week that "Grateful Doe" was indeed Mr Callaghan.
His half-sister Shannon Michelson told The Guardian: "I’m glad it was solved, but I’m also incredibly sad because I wanted so badly to reconnect with him."
Kind-hearted amateur detectives have been celebrating their discovery on Facebook.
One volunteer wrote: "The news we have been waiting for… I've been sitting here for how long in shock both for the sadness of his family and the fact that here on Facebook we are making a difference."