The St. Vrain massacre was an incident in the Black Hawk War. It occurred near present-day Pearl City, Illinois in Kellogg's Grove on May 24, 1832. The massacre was most likely committed by Ho-Chunk warriors who were unaffiliated with Black Hawk's band of warriors. It is also unlikely that the group of Ho-Chunk had the sanction of their nation. Killed in the massacre were United States Indian Agent Felix St. Vrain and three of his companions. Some accounts reported that St. Vrain's body was mutilated.