well, we can't be sure that they actually know who they've caught.
it's been ages since Roger's time, and he doesn't seem to be in special containment. therefore (considering what they did to Tom) I don't think they know who he is.

he probably just got bored and took a nap there. and woke up in jail, and doesn't have any good reason to get out (until now).

most likely that all the rookies are looking for him now. which is why they're all in town.