R.I. Assistant AG Arrested for Trespassing in Wild Police Body Cam Video

A Rhode Island prosecutor tried to school the police on the law ... but she got schooled herself and slapped with handcuffs for trespassing and creating a wild scene outside a restaurant with her friend, according to body cam footage.

Devon Hogan Flanagan -- a Special Assistant Attorney General -- even had the audacity to tell the arresting officer that he would "regret this" as he cuffed her and put her in the back of a patrol car.

The body cam footage, obtained by TMZ, shows Flanagan repeatedly telling the cop that she's an "AG" while being escorted in cuffs to the patrol car.

The video also shows her ordering the cop and his fellow officers to turn off their body-worn cameras if a citizen makes such a request, which the police, of course, scoff at. State law prohibits officers from turning off their body cameras, for transparency reasons.

What's more ... Flanagan's buddy, Veronica Hannan, got really mouthy with the cops, telling them they needed to listen to Devon because she's a "lawyer" and refusing to leave the premises when directed by the officers.

As the cops try to arrest her, Hannan puts up a fight while dressed in an elegant gown. She twists her arms so the police cannot cuff her hands, and she breaks away at one point ... but then police are able to shove her inside another patrol car as she kicks and screams before getting the door slammed in her face

The Newport PD officers were first called to the scene Thursday night and spoke with staff outside Clarke Cooke House restaurant, where Flanagan and Hannan were allegedly trespassing.

In the police video, you can hear a staff member tell the police to remove them and Flanagan says they're not trespassing.