The Adeptus Arbites.

The Adeptus Arbites are the law enforcement organization that enforces the law in the Imperium of Man, members of the Adeptus Arbites are feared for their devotion to upholding the law and show no mercy to criminals, officers of the Adeptus Arbites are trained to act as the judge, jury, and executioner. The Adeptus Arbites are managed by a Lord Marshal, who acts as the chief of the entire department, he is a member of the High Lords of Terra and has the final say on whether or not a law should be implemented or repealed.

Equipment used by the Adeptus Arbites.

The Adeptus Arbites are equipped as seen fit to enforce the law but are also given weapons to fight small-scale battles if necessary, Arbites will often be called up to fight alongside a planet's PDF or Imperial Guard regiment to protect the planet in an invasion, though they have nowhere near as powerful equipment or good training as a guardsman, they are not to be underestimated as they are just as fearsome as any other on the battlefield. Aside from the firearms used by the Adeptus Arbites, the main melee weapon used by these officers is the stun baton, a long baton used to fight off and subdue criminals who attempt to fight back using a melee-oriented weapon or with other means, the stun baton can be set to a non-lethal setting which, upon contact, gives a jolt of energy to the target strong enough to make them go unconscious, there is also a lethal setting which gives a large enough jolt of energy to literally stop the target's heart, some officers of the Adeptus Arbites have had to use their stun baton on that setting but in life-or-death scenarios, most prefer to use their sidearm instead.