The mother of Alberto Nisman, the Argentine federal prosecutor murdered in January 2015, has formally requested that former President Cristina Fernandez de Kirchner be investigated for possible involvement with her son’s death.

Nisman, who had spent a decade investigating the Iranian-directed bombing of the AMIA Jewish center in Buenos Aires in July 1994, was found dead in his apartment on January 18, 2015 – one day before he was due to unveil charges at Argentina’s Congress that Kirchner and her government had negotiated a secret pact to exonerate Tehran of responsibility for the AMIA atrocity. On Wednesday, Nisman’s mother, Sara Garfunkel, filed a request with Argentine federal judge Julian Ercolini for the investigation of Kirchner personally in connection with the murder

While the initial official reports into Nisman’s death alleged that the prosecutor had committed suicide, a federal police report issued one year after Kirchner lost the Argentine presidency to centrist candidate Mauricio Macri concluded that the cause of his death was murder. Forensic evidence contained in the report indicated that Nisman was assaulted and beaten by two individuals. He was then shot through head with .22 caliber bullet while on his knees.

A separate investigation this year into the substance of Nisman’s 2015 complaint by Judge Ercolini has heightened speculation that the former government had a hand in his death. Among Nisman’s concerns was the unscheduled visit of Hector Timerman, Kirchner’s foreign minister, to the Syrian city of Aleppo in December 2011. At a meeting hosted by Syrian dictator Bashar al-Assad, Timerman reportedly negotiated an agreement with his Iranian counterpart to drop all claims against the five Iranians wanted by Interpol, the international law enforcement agency, in connection with the AMIA bombing. The secret pact also expanded commercial ties between Argentina and Iran.

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In her request filed with Judge Ercolini, Garfunkel alleged that there had been a “criminal conspiracy to the highest levels” in her son’s death, including manipulating the crime scene after the murder in order to make it look like a suicide. Garfunkel also called for further investigation of four of Nisman’s aides, including computer technician Diego Lagomarsino, who is alleged to have supplied the gun used to shoot the federal prosecutor.

Garfunkel said that the plan to kill Nisman was a consequence of his 2015 complaint against Kirchner, “in order to guarantee the impunity” of those officials – most prominently Kirchner – who negotiated the pact with Iran.

Appearing before Judge Ercolini’s federal inquiry on October 26, a defensive Kirchner portrayed the pact with Iran as “the diplomatic and peaceful solution by which both countries opted to resolve the dispute and allow the Argentine judicial branch to carry out the investigations required for the necessary progress of the (AMIA) case.” During the same hearing, Kirchner – who was elected to the Argentine Senate during October’s midterm election – dismissed the charge that she had knowingly colluded in a cover-up with Iran as “absurd and insulting.”