Sexual assaults. Planted drugs. Illegal choke holds.

We’ve learned quite a bit about police misconduct in the six months since SB1421, the landmark transparency bill from state Sen. Nancy Skinner, D-Berkeley, went into effect on Jan. 1.

But the biggest thing we’ve learned is that many police departments believe that compliance with the law is optional.

SB1421 requires police departments to release internal affairs records, many of which had been under seal for decades, documenting serious incidents including use-of-force incidents, sustained findings of sexual assault, and sustained findings of police dishonesty. Previous to SB1421’s passage, California had some of the strictest confidentiality standards for police records in the nation.

But the public has the right to know about these very serious events, which is why it was so important to pass SB1421.

Another reason we know why SB1421 is important?

So many police departments are resisting compliance.

The California Highway Patrol, for example, employs more than 7,300 officers but has yet to produce the records required under the law.

Media organizations have reported that their requests to many large police departments, including Long Beach, have not been honored. San Jose, California’s third-largest city, hasn’t released any of the new law’s required, requested documents yet.

The San Francisco Police Department has released only documentation from a handful of officer-involved shootings, and no disciplinary records.

“Law enforcement in San Francisco is deliberately sandbagging the release of these records,” Jacque Wilson, San Francisco’s deputy public defender, said at a June 5 police commission meeting. The public defender’s office has discussed litigation in an effort to speed along the release of the records.

Other police departments have attempted to avoid their responsibilities under the law by charging exorbitant fees for the records.

Finally, some police agencies — Fremont and Morgan Hill are among them — destroyed their internal record archives dating before Jan. 1.

This is lawless conduct, and it’s depriving the public from the right to know about the activities of police in their communities.

Police groups even tried to avoid complying with SB1421 by pushing a novel argument in the courts.

They claimed that the law did not apply to records dated before 2019. Two different courts ruled against them.

But the fact that these groups have had a powerful champion in their attempts to deny the public this information — Attorney General Xavier Becerra — is another signal that this fight isn’t going away anytime soon.

To her credit, Skinner isn’t giving up. She’s planning to call for oversight hearings, and has said she’s open to amending the bill to require agencies to release records more rapidly.

Sadly, both of these actions may be necessary.

Another option may be for interested parties — including news media organizations, free speech advocates, and, in some cases, city attorneys — to force compliance through the courts.

This action would be expensive, time-consuming and slow. Becerra’s obvious bias toward the police groups could prove an obstacle, too.

But doing nothing is not an acceptable option.

The passage of SB1421 was a hard-fought battle to give the public transparency about police misconduct in their communities.

No one — least of all the agencies that have sworn to protect and serve the public — should be allowed to thwart the law.

This commentary is from The Chronicle’s editorial board. We invite you to express your views in a letter to the editor. Please submit your letter via our online form: SFChronicle.com/letters.