The man is recording some police officers from his own garage and some thug cop out of nowhere walks up to him and tries to steal his phone under the obvious lie it's supposedly "evidence."
"I'ma take the phone... 'cuz that's gonna be evidence... (Man refuses)... You want to go to jail?... Withholding evidence."
It's clear from the way he's acting it's pure brazen intimidation and thuggery.