Agents from Rio's Interpol office arrested 63-year-old former army officer Norberto Raul Tozzo, sought since 2005 when an Argentine judge ordered his arrest, and that of nine other former state security agents, an Interpol officer said by telephone.

The officer, who declined to be identified because he is not authorized to speak to the press, said only Tozzo had managed to avoid arrest in the Dec. 13, 1976, killings of 17 political prisoners in northern Argentina, near the Chaco province capital of Resistencia.

The killings _ known as the "Massacre of Margarita Belen" for the location where they occurred _ took place near the beginning of a bloody crackdown against dissent by the seven-year dictatorship.

Military officials initially claimed the 17 died in a firefight after armed leftist guerrillas attempted to free them. But investigators determined the prisoners were led away and shot without putting up resistance.

Nearly 13,000 people are officially reported as missing during the dictatorship's "dirty war." Human rights groups say the toll is closer to 30,000.

Tozzo was taken to Rio's Ary Franco prison, where he will await the outcome of extradition proceedings, the officer said.

"He was leading a completely clandestine life with no passport or any other form of identification," the officer said. "But when we detained him, he identified himself as Tozzo and did not resist arrest."

He said that in 2006 Rio's Interpol office began receiving information from Interpol Argentina indicating Tozzo may have taken refuge in Brazil.

"Little by little we put the pieces of the puzzle together and we nabbed him today," the officer said declining to give more information on how Tozzo was located.

He said he had no idea how long Tozzo had been living in Brazil nor how he sustained himself while in hiding, "But he must have been receiving a sizable amount of money, judging from the elegant clothes he was wearing and the hotel in which he was staying."