It is clear that Phoebe's murderer is one of the principal witnesses, and that this person is likely to have also murdered Boone. After nine of the ten cylinders are discovered in Phoebe's apartment, both Wolfe and Inspector Cramer become convinced that the missing cylinder is key to the murder, but political pressure forces Cramer's superiors to replace him with Inspector Ash. Ash issues a warrant for Wolfe and Archie and tries to bully information out of Wolfe, leading to a violent confrontation in the police commissioner's office. Although Wolfe stubbornly refuses to assist Ash, once the warrants are vacated he reveals why the cylinder is so important—on it, Boone identifies his own murderer. Phoebe, a passionate BPR supporter, intended to reveal it once the NIA had been damaged as much as possible by the controversy over Boone's death, but managed to alert the murderer that she was aware of his identity and was killed for her silence.