Ron Garretson was a bloody mess after crashing his car and slightly before he got arrested for DUI -- but that doesn't mean he forgot his manners with cops.
The veteran NBA referee had blood all over his hands Wednesday as a Lake Havasu City police officer responded to the scene of the car wreck. In body cam footage, you can see Garretson was on his own two feet after hitting a tree ... but he seemed far from okay.
As the officer tries asking him questions to figure out what had happened, Garretson extends his hand for a shake -- but gets turned down .