Vickipedia

POLICE, military, has two significations—1st, the organized body employed within an army to preserve civil order, as distinct from military discipline; and 2d, a civil police with a military organization. The police of an army commonly consists of steady intelligent soldiers, who act under the orders of the provost-marshal, and arrest all persons out of bounds, civilians not authorized lo pass the lines, disorderly soldiers, &c.; they also attend to sanitary arrangements. As in all military matters, the police of an army possess summary powers, and a sentence of the provost-marshal is carried out immediately after it is pronounced.

Of civil police with military organization may be instanced, as specimens, the Gendarmerie (q. v.) of France, the Sbirri of Italy, and, in an eminent degree, the Irish constabulary.