Who killed the most people in the world?

There are different types of murder. Hitler was responsible for the extermination of 6 million Jews from the late 1930's until 1945. Joe Stalin was responsible for the deaths and executions of 15 to 30 million people between 1930 and his own death in 1952. The colonoization of the Western Hemisphere and the entire history of the United States evidences the deaths of more than an estimated 300 million people. The Roman Catholic Church is responsible for the deaths of an estimated 350 to 500 million Jews and Christians during an 800 year period commonly known as the Inquisition. Luis Garavito, of Colombia may have killed as many as 400 children in the 1990's.