Here's a long-lost 1937 report on police corruption in San Francisco:
In 1935, the citizens of the city of San Francisco were indignant when tales of police officers having amassed huge fortunes through payoffs, graft and bribery came to light. In a convulsion of civic anger, District Attorney Matt Brady and Mayor Angelo Rossi were pressed to act, and they hired private investigator and former G-man Edwin N. Atherton. The so-called Atherton Report prompted dozens of cops to quit or lose their jobs, some went underground, one killed himself and his family. The entire police commission was forced to resign and reports of police payoffs, staged raids on gambling houses and brothels, bail bond skimming, unpaid loans to public officials and other were laid at the door of the House of McDonough.
Lost for more than seventy years, here is the infamous Atherton Report.
The 1937 San Francisco Police Graft Report by Edwin Atherton (Thanks, hankchapot!)