Thomas encountered Arthur Fleck after the failed comedian confronted him over his mother's assertion that Thomas was his father. Thomas told Arthur that his mother is delusional and a fantasist who actually adopted and abused Arthur. Thomas also warns Arthur to never go near his son, Bruce again, after an incident in which Arthur tried to find Thomas at Wayne Manor.
In the wake of Arthur killing Murray Franklin live on television, riots erupt throughout Gotham City. Thomas, Martha and Bruce get caught in the riots after attending the cinema and try to avoid them by going down an alleyway. They are caught by a rioter wearing a clown mask who kills Thomas and Martha, sparing Bruce.