Early in the Perry Mason series, Gardner wrote of the LAPD as a corrupt organization who were not above wiretaps, coercion and torture. As the series progressed and he desired to make the books more palatable to his middle-class audience, Gardner changed Mason's police opponents. The buffoonish Sergeant Holcomb would be replaced by Lieutenant Tragg. It would be hard to think of the TV series having Holcomb, so the change was fortuitous.
The Case of the Baited Hook would be Sergeant Holcomb’s last major appearance in the series. Mason leads him around by the nose. The lawyer takes the time to dictate to the switchboard operator, Gertie, while Holcomb waits. Holcomb nearly arrests Mason after the lawyer has already named the guilty man and had him detained by the police. In order to stop Holcomb from pursuing the arrest, Mason plants a damaging account of the sergeant’s incompetence in the local newspaper. Struggling to deal with the publicity, Holcomb drops his case against Mason.The next book, The Case of the Silent Partner, introduces Lieutenant Tragg to the series. Holcomb’s behavior had become repetitive in the last few cases, and Gardner took the opportunity to replace the policeman with a brighter and more vivid opponent. While never mentioned outright, Della alludes to an incident where Mason got Holcomb transferred. Gardner would later say that Tragg represented the improved, less corrupt LAPD.
Tragg follows Mason’s every step and gives the lawyer more chances to defend his actions than did Holcomb. For the first few chapters of the book, the policeman and the lawyer work side-by-side to investigate the poisoning of a hostess. Once Mason has a client, the two become adversaries, and the case quickly becomes a competition as to who can properly interpret clues and solve the crime.