CSI: NY 4x21

Hostage

When a man takes hostages during a failed attempt to rob a bank, Mac offers himself in exchange for a hostage. Only condition is that he must prove that the bank robber did not kill the bank manager, whose body is found lying in a pool of blood in the vault. On the outside of the bank, the rest of the team works to process the evidence that Mac finds and stop the SWAT team from making matters worse.