Yo Soy Nisman - I am Nisman (file)
Yo Soy Nisman - I am Nisman (file) Reuters

The investigator probing the mysterious death of an Argentine prosecutor who was carrying out a politically explosive investigation has summoned a powerful former spy for questioning Thursdaylocal media reported.

Prosecutor Viviana Fein, who is leading the investigation into her late colleague Alberto Nisman's death last month, has ordered ex-intelligence agent Antonio "Jaime" Stiuso to present himself at her office Thursday morning for questioning in the case, said daily newspaper La Nacion, citing judicial sources.

Officials did not confirm the report, according to AFP.

Nisman was found dead in his apartment with a gunshot wound to the head on the eve of a congressional hearing at which he was expected to accuse President Cristina Kirchner of covering up Iranian officials' involvement in a 1994 bombing at a Buenos Aires Jewish center.

The bombing at the Argentine Jewish Mutual Association killed 85 people and wounded 300, the deadliest such attack in Argentina's history.

Nisman had exposed Iran's guilt in ordering the attack via its Lebanon-based terrorist proxy Hezbollah, and requested arrest warrants for five Iranian officials including former president Akbar Hashemi Rafsanjani.

On January 14, four days before he was found dead, the prosecutor filed a 300-page report accusing Kirchner and Foreign Minister Hector Timerman of trying to shield the Iranian suspects in exchange for oil.

Nisman's death has caused a political firestorm in Argentina, where 70% of people say they believe they will never know the truth behind it.

Kirchner has claimed that Nisman was manipulated by former intelligence agents who then killed him to smear her.

The president wrote on her Facebook page that Stiuso "was the one giving all the information that Nisman asked for and possessed."

A top Kirchner aide, Anibal Fernandez, said Thursday that "there are plenty of reasons for (Stiuso) to be questioned" because of his "extremely close relationship" with Nisman.

Stiuso reportedly spoke with Nisman on the phone for about 12 minutes the night before the prosecutor was found dead on January 18.

Stiuso, who joined Argentina's Intelligence Secretariat (SI) in 1972, is known in intelligence circles as Argentina's most powerful spy.

His lawyer Santiago Blanco Bermudez said he had no information on his client being summoned for questioning.

"I just found out from the papers. We haven't received anything. I'm going to approach the prosecutor to find out what's happening. I don't even know if (Stiuso) is in the country," he told radio network Vorterix.

Kirchner has ordered the dissolution of the Intelligence Secretariat, which she says operates with agents and methods dating back to Argentina's 1976-1983 dictatorship.

She wants to create a new Federal Intelligence Agency that would have reduced wiretapping powers and wield less influence on certain political cases. Two Senate commissions began debating the reforms on Tuesday.