Professional police agencies supervise their officers to identify problem officers. They then don't sit around waiting for these ticking timebombs to screw up bad enough, potentially victimize members of the public, before they intercede or move to discipline or terminate. Oftentimes "problem officers" can be identified and "saved" with remedial training.
Regardless, remedial training should be a part of an agency's system to improve their workforce, and document during progressive discipline.

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