Five states–California, Massachusetts, Rhode Island, New York, and Hawaii—don’t have authority to take away a police officer's certificate or license to continue serving after misconduct, says The American Prospect. In 44 states, a state agency—usually known as a Peace Officer Standards and Training Commission (POST)—trains incoming cops, sets minimum standards that qualify them to serve, and can revoke an officer's license for serious misbehavior. All local departments do background checks on new hires, but the quality of those investigations can vary wildly, especially when small or financially strapped departments are involved.
“A background check is only as good as the person doing it and how deep they want to go,” says Eriks Gabliks, director of Oregon's POST agency. Thorough background checks can be particularly hard when an applicant has resigned quietly from a previous police job in lieu of a termination or investigation. In those cases, the department they left might not be willing or able to share information about the circumstances. Even if a background check turns up past rogue behavior, a small department may go ahead anyway. Such agencies usually are in poor communities that can't afford high salaries, notes law Prof. Roger Goldman of St. Louis University, who has worked for 30 years promoting better policing standards and stronger revocation authority.