The bank robbers, minus the head honcho Dalton (Clive Owen), blended in with the hostages so they could appear as hostages and then confuse the cops during the interrogations of the hostages after the bank robbery (for example: the bank robber Stevie with big breasts, the "hostage" who took his mask off and got dragged on the floor and the Armenian guy). The bank robbers placed a microphone inside the drawer thing with the message that was given to the police so they could hear what the police were saying. By listening to what the police were saying, they could prepare themselves moments before the police would enter the bank. When the police enter the bank, the robbers (minus Dalton) blend in with the hostages (because everyone is dressed the same) and exit the bank. Everyone who exits the bank is asked their name and has their picture taken; why? because since everyone is dressed the same, everyone's a suspect. The police search the bank and realize that: no money was stolen, the guns the robbers were using are fake and the execution they witnessed was fake. Now, here's the big surprise: the reason why the robbery took so long and no money was stolen is because Dalton and his colleagues were building a fake wall so that Dalton could hide behind it for a few days. What Dalton and his colleagues stole was the contents of the bank chairman's (Christopher Plummer) box: an important document that links him to the Nazis (he made a lot of money during WWII) and some diamonds. Dalton left a Cartier diamond ring in the box for Frazier (Denzel Washington) to find with a note that says "Follow the ring"; another reason why he left the ring in the box is out of respect for the previous owners of the ring, who died in a concentration camp. Frazier investigates on the ring and figures out that it's linked to the bank chairman. He talks with the chairman but gets no answers about what he had inside the box. After a few days, Dalton comes out of hiding behind the fake wall of the storage room and exits the bank. On his way out, he bumps into Frazier. Later that night, Frazier finds a little diamond in his pocket and realizes that the man he bumped into at the bank was the head of the bank robbers. Dalton slipped a diamond in Frazier's pocket because during their conversations, Frazier mentioned that he's "too broke to be engaged."