In 1915 Haitian President Vilbrun Guillaume Sam was killed by a mob. In response, the United States ordered the to Haiti with Maj. Butler and a group of Marines on board. On October 24, 1915, an estimated 400 "Cacos" ambushed Butler's patrol of 44 mounted Marines when they approached Fort Dipitie. Surrounded by "Cacos", the Marines maintained their perimeter throughout the night. The next morning they charged the much larger enemy force by breaking out in three directions. The startled Haitians fled. In early November Butler and a force of 700 Marines and sailors returned to the mountains to clear the area. At their temporary headquarters base at Le Trou they fought off an attack by about 100 "Cacos". After the Americans took several other forts and ramparts during the following days, only Fort Rivière, an old French-built stronghold atop Montagne Noire, was left.