To convict Chauvin, the prosecution is painting the rest of the Minn. police as above reproach. The black police chief is very likable, soft-spoken and gentle. The training the police receive is excellent, very nuanced about how to treat people who might be high on drugs or otherwise unable to comply. The blonde training officer is a highly educated war veteran. Another black officer who was passing by, also very likable.
The narrative is that the rest of the police are great, and that Chauvin is the rogue cop. I'm sure it's the best strategy. If they depicted the whole police force as institutionally racist, it would be harder to convict the single individual. [There will be a trial of the other officers too, who stood by and didn't prevent the murder.]