High Quality Content by WIKIPEDIA articles! 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.