You can't have 'eavesdropping' in an open air public setting. The officer was performing his ordered public duty and the eavesdropping charge is intentional abuse of authority. A good lawyer would eat him alive in court. He should have done like the rest of the LEO chickens that stop recordings citing "I was in fear for my safety" crap.
More of these cops need to be held PERSONALLY civilly liable for their misuse of authority.
Attach their houses to the lawsuits. That’ll get their attention.