(Capcom's primary storyline)
Thomas was an elderly worker employed at a sewage treatment plant next to the Raccoon Police Station. Thomas was described as being caring and kind to his fellow employees. He was also a professional chess player, loving the game so much, he fashioned his keys into chess pieces, and took to playing matches against his co-workers.
Thomas was infected with the t-Virus in early September, which gradually got worse as time went on. In order to stop himself from thinking about consuming human flesh, Thomas constantly smelled and devoured roast beef sandwiches, which he brought with him to work. He presumably ended up succumbing to the infection and became a zombie or was killed before that.
- The English version of "Watchman's diary" described Thomas as a scrapyard worker, though the Japanese version refers to it as a waste treatment center.