Argentina's foreign minister pales at the thought that anyone would compare the country's current scandal with Argentina's dark past known as the "Dirty War." In his first in-depth U.S. television interview, Hector Timerman dismisses talk that the mysterious death of a prosecutor about to charge him and the country's president with serious crimes is anything like the "terrible" times three decades ago. Timerman speaks to Lesley Stahl about the death of Alberto Nisman and the charges he made before his untimely death in a 60 Minutes report to be broadcast Sunday, March 8 at 7 p.m. ET/PT. An excerpt from Timerman's interview will be broadcast tonight on the CBS Evening News.

Nisman died from a bullet to the head just one day before he was to formerly present his case against Timerman and President Cristina Fernandez de Kirchner accusing them of conspiring to protect Iranian officials implicated in the 1994 bombing of AMIA -- the Buenos Aires Jewish community center -- that killed 85 people. All of Argentina is debating over whether it was suicide or murder. Some say it is reminiscent of the Dirty War.

"Nah, it's impossible,"scoffs Timerman. "We are talking about things that were terrible, terrible," he says, referring to the thousands who disappeared and died at the hands of the military junta or its proxies, including horrific executions when they were pushed out of aircraft over the sea or jungles.

Timerman says he will not speculate whether Nisman was murdered or killed himself, but denies the charges of the 51-year-old prosecutor. Nisman lay out his case in a 289-page report. He accused Timerman and Kirchner of seeking a trade deal with Iran in return for protecting the officials, a deal Timerman had secretly made with the Iranians. "Well, that's a lie. That's a total lie. I never said that. Nisman never showed any evidence that I said that," he tells Stahl. Furthermore, says Timerman, only a judge could rescind the standing order that Interpol detain the Iranian officials in question, which would have been part of any deal.

Stahl also speaks to the last known person to see Nisman alive. In a rare interview, Diego Lagomarsino was a tech worker in the prosecutor's office. He gave Nisman a gun - the one that was used in his death - because the prosecutor said he wanted additional protection; Lagomarsino says Nisman told him he did not trust his 10 bodyguards. Nisman was very upset, recounts Lagomarsino, "He told me, 'Do you know how it feels that your daughters don't want to be with you because they are afraid that something will happen to them...', I had never seen Nisman so concerned," he says.

The latest twist in a tale that has transfixed Argentinians and captured the world's attention is what a forensics report commissioned by Nisman's ex-wife concluded: he was murdered and that his body was moved after his death.