Thomas A. Constantine, Administrator, Drug Enforcement Administration, reported to the House Subcommittee on National Security, International Affairs and Criminal Justice, concerning how organized crime groups from Mexico operate and affect many aspects of life in America. He claimed that sophisticated drug syndicate groups from Mexico had eclipsed organized crime groups from Colombia as the premier law enforcement threat facing the United States. Although the leaders of these criminal organizations are known to American law enforcement and have been indicted repeatedly, they have not been located, arrested or prosecuted. They are protected by corrupt law enforcement officials, despite pledges of cooperation from the Government of Mexico. The report includes biographical data on the Cali Group and major traffickers from Mexico; discusses the effect of Mexican organized crime on the United States; reviews US law enforcement strategy against organized crime in Mexico; and describes cooperation with Mexico.