Picnic in Minnesota of Refugees from the US-Dakota war of 1862.
The daughter of Mr. Schwandt, enceinte [pregnant], was cut open, as was learned afterward, the child taken alive from the mother, and nailed to a tree. The son of Mr. Schwandt, aged thirteen years, who had been beaten by the Indians, until dead, as was supposed, was present, and saw the entire tragedy. He saw the child taken alive from the body of his sister, Mrs. Waltz, and nailed to a tree in the yard. It struggled some time after the nails were driven through it! This occurred in the forenoon of Monday, 18th of August, 1862.
Picture sourced from Library of Congress via Retronaut.
Quote sourced from “Bryant, Charles S.; Abel B. Murch (1864). A history of the great massacre by the Sioux Indians in Minnesota : including the personal narratives of many who escaped.” Via Wikipedia.