Everything you described, sounds like a LE Officer - perhaps a Detective for the Sheriff's Office or for the District Attorney, U.S. Marshal, etc. (these guys if detectives, wear coats and ties.....) except for him putting the pistol in his waistband on the way over to the sedan......it doesn't sound like LE that would but a pistol in their waistband. The gun the alleged LE Officer put in his waistband, doesn't have a body-mounted holster? Odd.......

That one is throwing me.......why he would risk not having his handgun in-hand as he approached the perp(s) in the sedan. OTOH, if the aggressor believed that he had sprung a surprise on the soda cup tossing driver, that had no idea he was tossing his drink at a LE Officer of some type - the Officer (if it was an Officer) felt he had the situation assessed as being 'waistband worthy' and not drawn down on the car with his firearm as he approached the perps in the vehicle.

Cuffing them on the ground, was likely the right way to detain the occupants that had decisively and maliciously tossed it on another car in traffic - and likely going to light-up any LE Officer in plainclothes and plain-wrapper-vehicle. I say hoorah for the citizens today - if in fact the person doing the cuffing was actually LE.....