Alberto Nisman, lead prosecutor in the two-decade-old case, was found dead with a gunshot wound to the head in his home Sunday -- one day before he was to go before a congressional hearing to accuse Kirchner of shielding Iranian officials implicated in the attack which left 85 dead.
Investigators have said Nisman appeared to have committed suicide, but have not ruled out homicide or an "induced suicide."
"I'm convinced that it was not suicide," Kirchner said.
"Prosecutor Nisman's charges were never in themselves the true operation against the government. They collapsed early on. Nisman did not know it and probably never knew it.
"The true operation against the government was the prosecutor's death after accusing the president, her foreign minister, and the secretary-general of (her political faction) of covering up for the Iranians accused in the AMIA attack," she said.
But aides in recent days have pointed to former intelligence officials who were recently fired, including the former chief of operations of the Intelligence Secretariate, Antonio Stiusso, who worked closely with Nisman.
Before his death, Nisman had filed a 280-page complaint charging that Kirchner had issued an "express directive" to shield a group of Iranian suspects in the 1994 bombing.
Nisman contended that the government had agreed to swap grain for oil with Tehran in exchange for withdrawing "red notices" to Interpol seeking the arrests of the former and current Iranian officials accused in the case.
Opposition leaders denounced Kirchner's charges as an opportunistic about-face.
"It's very serious. To go from supporting the thesis of a suicide, to an assassination, she must assume the consequences," said Senator Ernesto Sanz, a member of the opposition.
