context: The action is set in an unnamed American city and is told mainly in flashback, and flashbacks within flashbacks.
  The Terrified Witness[edit]
  Under heavy police protection, gangster Joe Rico (Ted de Corsia) arrives late at night at the courthouse to testify against crime lord Albert Mendoza (Everett Sloane). There have been several attempts on Rico's life and he is a bag of nerves, but lead prosecutor ADA Martin Ferguson (Humphrey Bogart) reminds him that he himself faces plenty of charges that could "burn you a dozen times". Ferguson is bound and determined to get Mendoza "in the electric chair" and stresses to Rico that Mendoza will "die, he's got to die, and you're going to kill him."
  After yet another attempt on his life, Rico gives his bodyguards the slip and tries to escape by reaching the fire escape on the eighth floor of the building, but he falls off the ledge and is killed on impact when he hits the courtyard.
  Rico was the only evidence Ferguson had against Mendoza, who will walk away in the morning as a free man. However, he believes that something else came up in the course of the investigation that might make the caseâif only he could remember it. He and police Capt. Nelson (Roy Roberts) decide to go through the evidence hoping that something will come up.
  The Original Investigation[edit]
  The case began when a distraught man named James "Duke" Malloy (Michael Tolan), a small-time gangster and strongarm-man, burst into a police station and claimed to have killed his girlfriend, under pressure from others. At the crime scene, which is out in the countryside, the police find an empty grave. Malloy, overcome with grief, bitterly explains that his girlfriend was a "contract" and a "hit", terms which mean nothing to the officers. He later commits suicide in his cell.
  Ferguson, the ADA in charge of homicide, is brought in on the case. Malloy only had convictions for petty crimes, not murder, but a check of his associates leads the investigators to "Big Babe" Lazick (Zero Mostel). Lazick refuses to talk, but when Ferguson threatens to jail his wife and put his little son into foster care, Lazick confesses that he is part of a "troop" (a group of killers) operating under the orders of Joe Rico who gets requests to commit murders over the telephone from a third party. The gang uses terms like "contract" (a request to commit murder) and "hit" (the actual killing) in case othersâmainly the copsâare listening in. The killers get a regular salary (even if they go to jail), their families are looked after if anything goes wrong and bonuses are paid for actual killings. Only Rico knows who the top boss is.
  The killers carry out murders for profit, the idea being that they are hired to kill someone at the request of someone else (the person's spouse or business partner, for example). The killer will have no motive for committing the crime and thus will not be suspected by the police, while the client with the motive will have a perfect alibi. Furthermore, the client has to keep contributing money in case of exposure.
  Lazick leads the police to the body of Nina Lombardo, Malloy's girlfriend whose murder started the investigation. It emerges that she was a contract whom Malloy was supposed to kill, but he instead fell in love with her. He tried to cover it up but his associates caught up with them and forced him to kill her. Nina's roommate, Teresa Davis (Patricia Joiner) tells the detectives that Nina's real name was Angela Vetto and that she was in hiding since her father's death. Ten years beforehand Angela and her father, a cab driver, witnessed the murder of John Webb, a cafÃ© owner.
  The police eventually find a mass grave filled with dozens of bodies. As the authorities close in on them, the gang begins to break up. Some go into hiding, fearing for their lives as others are killed by other members from out of town. Rico himself is hiding on a farm with his last remaining accomplices. He calls his boss, whose answers do not reassure him. Rico pretends to go to town for a contract but instead parks his car behind some bushes. He later witnesses his accomplices being murdered by a pair of hired killers sent by his boss to silence everyoneâincluding Rico.
  Rico contacts Ferguson. In return for being spared the death penalty, he offers to testify against his boss, Mendoza. Rico first met Mendoza when the latter tried to interfere in a bookmaking racket run by Rico's previous employer. Impressed by the beating he got from Rico, Mendoza took him to a cafÃ© and explained the concept of his new business: murder for profit. To prove his point he killed the cafÃ© owner, John Webb, for which he received $500. However, the killing was witnessed by Tony Vetto (Tito Vuolo) and his daughter. Mendoza and Rico got away, but years later Vetto recognized Mendoza as a cab fare and was murdered by Rico, on orders from Mendoza, before he could go to the police.
  Desperate Hunt[edit]
  With Rico now dead, Mendoza will walk. Frustrated, Ferguson goes to Mendoza's cell and leaves him with photos of his victims, warning him of the nightmares that they will give him. He then returns to the evidence room and listens to a tape made of Rico's confession â which is not admissible in court. In it, Rico describes Vetto's daughter as having "big blue eyes"; Ferguson remembered that Nina Lombardo (assumed to be Angela Vetto) had brown eyes. On the other hand, her roommate, Teresa Davis, did have blue eyes. Ferguson concludes that Nina was pointed out as Duke's contract by mistake. Teresa told the police that Nina was Angela Vetto as a hint: to get them on the trail of the killers without getting involved herself; she even tried to leave town, but Ferguson warned her against it.
  However, from Nina's photo, Mendoza has come to the same conclusion and, through his attorney, sends two of his remaining men after the real Angela Vetto. Ferguson and Nelson arrive at her house to learn that she has gone shopping. The streets are too crowded for them to find her, so Ferguson uses a music store's sidewalk loudspeakers to warn her that her life is in danger and to contact him at the store. Angela does so and Ferguson sets off to meet her, followed by the killers. In the subsequent shootout, Ferguson kills one of the gangsters and the other is arrested. He then escorts Angela Vetto to testify against Mendoza and put him in the chair.
question: Where did the bomb explode?
answer: Bathroom