Jason Harkness was an apprentice of the Gormogon.
It's mentioned in The Widow's Son in the Windshield that he went to six different good private schools, but was expelled from all of them because he used to attack people in their dorms while they were sleeping. He later received therapy and did some community service. Sometime in his past he had a diamond planted in one of his teeth. This would later cause markings on one of the Gormogon's victims, whose skull Jason ate from. The markings led Booth and Brennan to him and was enough to get a court order for his bite marks. Having nowhere left to go, Jason confessed and hinted that he had eaten and possibly killed more people. He was later found in his cell, stabbed in an act of suicide and placed in the same position as a silver skeleton found in the Gormogon's lair.