Vladimiro Montesinos Torres was the head of the national intelligence service in Peru from 1990-2000 and special advisor to President Alberto Fujimori. During the Fujimori presidency he directed human rights abuses, and ran a sort of mafia that controlled the media, government, and large business. He was wanted for crimes including fraud, money laundering, drug and arms trafficking, extorsion, illegal wiretapping, torture, murder and many others. In effect, he had almost complete control of the Peruvian government for roughly a decade. He was arrested in late 2000 in Caracas, Venezuela.
He was born in Arequipa, Peru in 1946 and trained at the US School of the Americas. In 1966 he graduated from the Peruvian Military School of Chorillos, becoming an army captain and working as an intelligence operative for the Sistema Nacional de Inteligencia. In 1976 he was charged with selling state secrets to the CIA, and was discharged from the army the next year.
He became a lawyer, collecting a fortune representing drug traffickers and police linked to drug trafficking. He was tried in 1983 by a military court for treason (he was accused of attempting a military coup with an underground newspaper) and acquitted. He defended then presidential candidate Fujimori in 1990 against accusations of real estate fraud. The charges were quietly dropped and paperwork for the case went missing.
Montesinos' Grupo Colina was found to be responsible for the Barrios Altos massacre, in which 15 people were killed in November 1991. In July 1992, 9 students and a professor at La Cantuta University were abducted by security forces (also found later to be Grupo Colina) and later murdered. The case was moved from civilian to military courts, with no justice being served.
The CIA supplied Montesinos with at least $10 million from 1990 to 2000 as well as surveillance equipment. He made an arms deal with the leftist FARC rebels in Colombia, basically diverting the funds to the group that the CIA is fighting in their unsuccessful War on Drugs. The CIA then released hundreds of videotapes in which Montesinos was seen paying off politicians, journalists and business leaders, which led to his arrest and Fujimori's resignation.
Sources:
http://www.desaparecidos.org/peru/tort/montesinos/eng.html
http://www.gci275.com/peru/montesinos.shtml
http://www.public-i.org/story_01_062701.htm