In 2002, he aided Stephen in his assassination attempt on Sherilyn Harper and escaped from the security guards when it failed. Convinced by Stephen's belief that Harper was the host of a malevolent alien entity (unaware that he was the Fearmonger's host), he made his own attempt to assassinate her, but was stopped by the Seventh Doctor and Ace.
Determined to stop Harper, and upset that the Doctor refused to take her down himself, Walter contacted Alexsandr Karadjic and joined the United Front. He aided them in committing several terrorist acts, but this instead generated more fear until riots broke out in the city. Traumatised by the violence he helped cause, Walter was taken to an institution for treatment after the Doctor stopped the riots. (AUDIO: The Fearmonger)