He is best known as the Colonel Commandant of the 2nd Foreign Parachute Regiment 2e REP, who directed the military intervention in Zaïre against the Katanga rebels responsible for several massacres. It was the success in the Battle of Kolwezi which resulted in the liberation of the majority of the Katanga rebels' hostages. However, Erulin was later accused of having used torture during the Algeria War; an accusation that remains unsubstantiated and controversial.