Alberto Nisman was found dead inside his luxury Buenos Aires apartment on Sunday with a handgun that was not his own and a shell casing found beside his body.
Nisman had only last week filed a 300-page presentation to a Buenos Aires court alleging that de Kirchner had conducted secret negotiations with Iran through non-diplomatic channels to cover-up Iran’s alleged involvement in a 1994 bombing of a Jewish community centre in Buenos Aires that left 85 people dead.
The AMIA centre attack remains unresolved, but suspicion fell on key Iranian diplomatic personnel active in Argentina at the time.
Nisman claimed that de Kirchner was willing to cancel an international arrest warrant for a senior Iranian diplomat in exchange for an oil-for-grain deal with the sanctions-hit Middle Eastern state.
The accusations, which were dismissed at the time by de Kirchner’s office as “ridiculous”, were based on alleged phone taps on close aides to the president.
The UK’s Guardian newspaper quoted Viviana Fein, investigating prosecutor into Nisman’s death, as saying a preliminary autopsy found there was “no intervention” in his death.
“The firearm belonged to a collaborator of Nisman,” Fein told Todo Noticias television channel. “He had had it a long time.”