From my research on this subject i have learned that historians believe that the 21 French traders who were killed in 1736, were killed by the Dakota or, the Sioux. However, the Dakota or, the Sioux, were willingly trading with the French who had established French trading posts in the Minnesota territory of the Dakota or, the Sioux. In 1736, it was the French who had well armed the Dakota or, the Sioux, with the latest European weapons or guns, which they used on the Anishinabe, Assiniboine and Cree. What that represents is obviously great discontent was being felt by the Anishinabek, who were at war against the Dakota or, the Sioux, against the French, who were also freely trading with the powerful Anishinabek. Unfortunately, the French would learn in 1736 that the Anishinabe would not tolerate the French trading with their bitter DAkota or Sioux enemy.
It was not the Dakota or, the Sioux, who killed those 21 French traders. Those 21 French traders were killed by the Anishinabek. The Anishinabek had at least one motivation to kill the 21 French traders, and that was to prevent the Dakota or Sioux from acquiring European guns. What followed next was not fair to the Dakota or Sioux people. After the Dakota or, the Sioux, had lost their supply of European guns, it did not take the Anishinabe, Assiniboine and Cree too long to drive them out onto the plains of of South Dakota and Nebraska.