Washington, D.C. ? Republican Sen. John McCain served on the advisory board to the U.S. chapter of an international group linked to ultra-right-wing death squads in Central America in the 1980s.

The U.S. Council for World Freedom also aided rebels trying to overthrow the leftist government of Nicaragua. That landed the group in the middle of the Iran-Contra affair and in legal trouble with the Internal Revenue Service, which revoked the charitable organization’s tax exemption.

The council created by retired Army Maj. Gen. John Singlaub was the U.S. chapter of the World Anti-Communist League, an international organization linked to former Nazi collaborators and ultra-right-wing death squads in Central America. After setting up the U.S. council, Singlaub served as the league’s chairman.

McCain’s tie to Singlaub’s council is undergoing renewed scrutiny after his campaign criticized Barack Obama for his link to William Ayers, a former radical who engaged in violent acts 40 years ago.