In order to place someone under arrest (collar a perp) , place left hand on shoulder and the right hand on the biceps. Although bicep was stated, the way it was illustrated it seems the right hand was more on the forearm.
The word "Copper" in its original form was used to mean "someone who captures".
A letter carrier escort is when a postal inspector(s) shadows a letter carrier into the more dangerous areas where robberies are on the rise. The main objective is to protect employees. Mail Delivered; Carrier Safe; Mission Accomplished.
One aspect of night duty, entails staking out and surveilling post offices.