Retraining won't do anything. They might refrain from the behavior for maybe 1-2 months of their murder if you think you will get away with attitude. Then go right back to business as usual when things cool down. What we need is police department administrators who aggressively investigate applicants' backgrounds. Weed out those aligned with hate groups, gang associations, violent lawbreaking, whether domestic, robbery, and such. Look very carefully at their social media presence. Further, subject them to evaluations such as DISC, HEXACO, MBTI, or EPI - or similar. All to weed out undesirables before they are hired and become a problem. I think also retested with similar tools once every 3-4yrs, as people do change. When a pattern of disciplinary behaviors begin to manifest themselves, get rid of them at the third strike, and collaborate with in-state and out-of-state PDs to prevent them being hired as cops elsewhere. Finally, when they do break the law, treat them the same way any citizen would be treated by the legal system if they broke the same law. Only then will we have a truly accountable law enforcement that citizens trust.
If it hasn't already begun, we will see ever more increasing incidents of citizens targeting cops, deliberately shooting them, seeking to hit them with vehicles, even baiting them into places to kill them. People are slowly now having an attitude of when stopped by a cop for whatever reason, get them first because they already have murderous intent toward you. I just don't like what I'm seeing developing in the here and now.
Now, watch what the blindly blues do.