This dude used to work at the Patent Hall, and he's the one who ran off with Marjorie's machine. His dad, Louis Trout, also worked there, but as the head patent officer. Coincidence? We think not.
We get confirmation that the Trouts are in league with Snatcher when Arthur overhears a convo where Gristle is talking to another minion about how the Trouts had to tangle with some trotting badgers. The minion states: "'Old Trout won't be able to sit down anytime soon, and Trout Junior is lucky he still has a nose'" (23.14). Seems harsh but let's remember, they're thieves and not very nice people (given that they are helping Snatcher try to take over Ratbridge). Snatcher betrays Edward, though, by shrinking him and his father, which is a (well-deserved) bummer for them.