"Behind closed doors, we call it testilying," a New York City police officer, Pedro Serrano, said in a recent interview, echoing a word that officers coined at least 25 years ago. "You take the truth and stretch it out a little bit."

An officer lying under oath in order to sway a verdict calls into question every single police report or court testimony from that officer.

You're absolutely correct. This is extremely serious.

Are there public databases that track dishonest officers? That could be incredibly helpful to defence lawyers.

1. Are public court-records complete enough to show it?

2. Is it a judgment-call whether a given record shows it?

3. How would list-makers avoid charges of defamation?

4. How do they prevent spam?

  a. link to case's public testimony (CPT)
  b. text in CPT to officer's statement.
  c. text in CPT that contradicts the statement.

2. Innocent until proven guilty? I'd say best to start with the clear lies first to build the list's credibility. However enough borderline cases surrounding an individual or department can also be interesting.

3. Defamation requires that the statements about the person be false. Referencing court docs about what they said should obviate that concern. Maybe the trick is to bill the db as a "list of inconsistencies" rather than outright lies.

4. I'd be more concerned about DoS attack rather than spam.

I had in mind a service where people were allowed to write in their claims of testilying -- how do you prevent it being "spammed" by every criminal with a grudge against a cop.

By asking them to cut and paste text from CPT -- which can then be electronically verified, you can cut down on the casual attempts. Of course a real attacker can get around that trivially.

Another question is where to host it. While truth is a libel defence in the US -- I am not sure that is true in other countries.

Even if it may not be technically true, it's safe for the general public to assume this.

And it's extremely common.