Even if they have jurisdiction, I still have concerns about the insurance, liability, and officer safety side of things (lack of radio communications with nearby backup) since this is obviously not an on-duty activity. Officers working off-duty are sworn, but they're not acting under the supervision or on behalf of their department when working off duty, so their department could decide to let them twist in the wind rather than defend their actions in a lawsuit. That's not to say they're incapable,