At the beginning of World War II, Dirlewanger volunteered for the Waffen-SS and received the rank of Obersturmführer. He eventually became the commander of the so-called Dirlewanger Brigade (at first designated as a battalion, later expanded to a regiment and a brigade, and eventually a division), composed originally of a small group of former poachers along with soldiers of a more conventional background. It was believed that the excellent tracking and shooting skills of the poachers could be put to constructive use in the fight against partisans. Later, Dirlewanger's soldiers were mostly recruited among the ever-increasing groups of German convicted criminals (civilian and military) and concentration camp inmates, eventually including mental asylum patients, homosexuals, interned Romani people, and (at the end of the war) even political prisoners sentenced for their anti-Nazi beliefs and activities.