For decades, California police chiefs and sheriffs have lamented how difficult it is to fire officers and deputies who act with dishonesty or brutality, blaming powerful labor unions and robust employment protections.

What law enforcement leaders have not revealed, and what has remained a secret until now, is how they have repeatedly turned to an under-the-radar method of getting rid of problem officers — one that not only allows the officers to avoid accountability but, often, to quietly move on to other jobs where they are asked to protect the public.

For years, dozens of California police agencies have executed “clean-record agreements,” clandestine legal settlements that promise to hide the wrongdoing of an officer in exchange for the officer’s guarantee to leave an agency without a fight, an investigation by the San Francisco Chronicle and UC Berkeley’s Investigative Reporting Program found.