Matt Jones was a Special Forces Major who was taken prisoner while on deployment in Iraq.
While on deployment in Iraq, Matt was captured by insurgents and held in the Najaf Cemetery. While prisoner, Matt became infected with multiple khan worms. Eventually, Rick Willis and Kit Verson were sent in to rescue him. By the time Matt was found, he had become severely dehydrated with cracked skin. Matt attacked his captors, infecting both men with multiple khan worms before they were forced to kill him in self-defense. In the official report, the rescue mission was claimed to be a failure and Matt was supposedly killed by his Iraqi guards.
After returning from deployment, Rick and Kit fell under the same affliction as Matt due to the khan worms that he had infected them with. While teaming up with hunters Sam and Dean Winchester, former US Marine Cole Trenton was able to get the details of Rick and Kit's last mission from a friend of his in Military Intelligence. Cole's friend was able to send him helmet camera footage of the failed rescue mission which included Matt's state and attack on Rick and Kit. The footage ended before Matt was killed, but the Winchesters and Cole were able to put together what must've really happened for themselves.