Who is the fourth character? The one who gets shot in the bank.

I hope somebody can help me here. I am wondering who the guy that Dillon's character shoots in the head in the bank robbery is. I thought they might have picked up his body and taken him along and he is alive but they were 4 guys other than Dillon. The guy shot in the bathtub, the dentist, and Steve Zahnn's character. Those are three. The fat guy wasn't the one since we see him in the end and the woman was in the bank with Dillon. Could the guy had been the one with the guy (in the bathtub) when they were telling Steve's character that they want the money in the strip club? Sorry if the post is confusing, but I just saw the movie and I'm a little confused myself.

Oh and to adress all the other threads: The movie is over-rated. I liked it but it was over-rated. And like some other posters said, the twists were only there for the sake of a twist. And half of them could be seen from a mile away. Like when they shoot Dillon and take him in the van, you know he was in on it. You know the woman will shoot him, and that he will shoot the his friend. Same as for the car getting hit by the bus.
Prison Break *bleep*ing rules!!!!