Cairo, a gash over his eye, stands with a gun over Brigid as she huddles, terrified, in the chair. Brigid claims he struck her first, but Cairo tells the police that she and Spade attacked him after he was let into their apartment and that she threatened to murder him. Aloof and hovering by the door, Spade stays quiet until the police threaten to arrest all of them.
Since the reader has little idea about what happened between Brigid and Cairo, this scene forces us to imagine what went on inside. Depending on one’s view of Brigid’s ethical integrity, she could appear as the aggressor or the victim.
Not wanting the police to bring them to the station, Spade tells Dundy that the three of them were just playing a practical joke on him. Spade claims that before answering the door, he told Cairo to call out to the police in order to get the police tense and nervous for no reason. Cairo, who doesn’t want to go to the station either, agrees and says he got the gash from tripping over himself. Knowing that Spade is hiding the truth, Dundy snaps and hits Spade in the face. Before Spade has a chance to hit him back, Polhaus gets between the two men and prevents the fight.
Although the story is preposterous, the officers have no evidence to prove that they are lying. Without evidence, the officers are powerless. In an example of aggressive masculinity, this powerlessness provokes Dundy into trying to regain some power by hitting Spade. Just as aggressive, Spade doesn’t care that Dundy is a cop and would have hit him back if not for Polhaus’ intervention.
Cairo and Brigid confirm that it was all a practical joke. Spade tells the police that if they bring them to the station, the newspapers will ridicule the cops for arresting people on the basis of a practical joke. Angry but not wanting to be embarrassed, the cops decide to leave. Cairo leaves at the same time as the police, despite Spade’s warning that they will question him.
The cops know Spade is lying but they don’t want to risk looking like fools in the paper so they let them all go. This scene show just how good Spade is at manipulating the incompetency of the police.