In the 1970s, Los Angeles police officers were furious that past complaints against them increasingly were making their way into court cases.

So LAPD officials did something radical: They took more than four tons of personnel records dating to the 1940s and shredded them.

That decision resulted in the dismissal of more than 100 criminal cases involving officers accused of wrongdoing whose records had been purged, sparking public outrage.

The Legislature responded by passing a law that ensured officer discipline records would be preserved — but also made it nearly impossible for anyone to learn about them. The action, driven by police unions, began a decades-long process that has made California the strictest state in the nation when it comes to protecting police confidentiality.

That could change in the next few weeks, with lawmakers in Sacramento considering a landmark effort to increase disclosure.