seriously just take away their guns. it's become clear that police can't be trusted to use them responsibly. if there's a shooting type situation then an armed SWAT team can be called in (it's what happens already anyway).
police in the UK don't carry guns and everything is fine, there's minimum police killings vs the 1,000 per year in the US
I think that so long as you have an armed citizenry, it's difficult to justify an unarmed police force. That's why cops in the UK are able to get away with NOT carrying. The Firearms Act, passed incrementally over the last 100+ years, makes it incredibly difficult to lawfully own a firearm in England.