The United States Central Intelligence Agency (CIA) has been accused of involvement in the trafficking of illicit drugs. Books and journalistic investigations on the subject that have received general notice include works by the historian Alfred McCoy, professor and diplomat Peter Dale Scott, journalists Gary Webb and Alexander Cockburn, and writer Larry Collins. These claims have led to investigations by the United States government, including hearings and reports by the United States House of Representatives, Senate, Department of Justice, and the CIA's Inspector General. The various investigations have generally not led to clear conclusions that the CIA itself has directly conducted drug trafficking operations, although there may have been instances of indirect complicity in the activities of others.