It's an old show now, so, spoilers, no, yes? So the Trinity killer (played by John Lithgow ....Trinity rock from the sun?) picks up his car from the detail shop in the afternoon, stops by Dexter's house and murders Rita. His car breaks down that night, and Dexter, having removed a part from the engine catches up with him. So when did Dexter have the time to do that, and if he was following all along, how come he didn't catch him before he went into the house to do Rita in? We don't see a stop at a service station or anything like that and the DVD contains no deleted scenes.