Jack Thomas was Jennifer and Andrew Fellows' neighbour. He found out that Jennifer Fellows is Jennifer Blood, and wanted to help her, thus becoming a vigilante himself, though not a very good one.
Major Story Arcs
As Jennifer Blood was going to kill Pete Blute, her uncle, Jack followed her, thinking she was going to some sort of sex party, only to find that she was killing someone. After he found out that she was a vigilante, he decided he wanted to help her, and she let him live.
Jack noticed someone suspicious lurking around outside, but they realised he was looking at them, and they attacked him, beating him up and even popping one of his eyes. Jennifer showed up and defeated Jack's attacker. Since Jack only wanted to help Jennifer, Jennifer said that there was one thing she needed help with, to which Jack was willing to do. However, Jennifer knocked jack unconscious and strapped a bomb to him and set it on a timer. She then typed an e-mail detailing that Jack was the Jennifer Blood Killer, and sent it from Jack's computer. The detectives Fulsom and Pruitt stopped by to follow up on a lead concerning a pair of stripper pants, however, they were not aware of the e-mail or the bomb, and thus, when the bomb exploded, Jack and Fulsom were killed, leaving Elaine in critical condition.