Watch the Buffalo Protester Do Something Weird and Creepy

We've all seen the horrible incident where Buffalo police push an elderly protester to the ground. No excuse for their treatment of him. But, no one has focused on his bizarre behavior. Why did he approach them and why did he then take the device in his hand (it appears to be his phone) and rub it on the cops? See if you can figure out what he was doing - here it is in slow motion: