Unbeknownst to Vinnie, his car was used in the robbery where an off-duty cop was killed, leading to his arrest and brutalization at the hands of the NYPD. Frank bails him out, then reluctantly lets Vinnie continue his pursuit of Knox Pooley. Vinnie tells Ritchie he's a cop and asks him to help him gather evidence against the Pilgrims. Vinnie goes to a Pilgrim rally and stumbles across the truck that was used to kill Pete, then agrees to a meet with Stan in the hopes of tying Pooley to it, leading to Stan and Ritchie's arrests. (source: http://www.plasticcow.com/wiseguy)