After Cannon asks various people around the pool questions about the mysterious blonde, Gorman goes into the apartment to talk to B.J. While they talk she is shown taking her blonde wig off twice; once when the camera shows her from her front side and then again when the camera's view switches to her back.
When Cannon is at the firing range asking for help from his friend on the police force he isn't wearing any hearing protection. Firing ranges are *very* loud, and not only would Cannon be suffering from ringing ears for some time, he likely would have suffered permanent hearing loss.
When Cannon is reading out loud the statements made by the witnesses of the incident, he quotes Dr. Samuel Calvert who says that Selden was trying to help the blonde girl when Bell attacked him. But this doctor, who was the one who checked Selden and pronounced him dead, hadn't been there when this happened, and had come from around the corner of the building, and he couldn't have seen anything about the attack.