Why did federal troops attack the Sioux Indians at wounded knee?

Federal troops attacked the Sioux Indians at Wounded Knee on December 29, 1890, primarily due to tensions arising from the Ghost Dance movement, which the U.S. government viewed as a threat to its authority. The army sought to disarm the Sioux, fearing that the movement could incite rebellion. The situation escalated when a scuffle broke out during the disarmament process, leading to an indiscriminate massacre of Sioux men, women, and children. This tragic event marked the end of the Indian Wars and symbolized the brutal suppression of Native American resistance.