/ Updated 

Argentina's President Cristina Fernandez said the death of a prosecutor investigating the country's worst terrorist attack was not a suicide, as was initially reported.

Alberto Nisman, the lead investigator into the 1994 attack of a Jewish center that killed 85 people, was found dead in his apartment late Sunday, a 22 caliber pistol by his side.

Nisman had accused government officials including Fernandez of trying to derail his investigation into the bombing, and was due to present his case to Congress hours before his death. Nisman charged the government had opened a secret back channel to Iran to clear suspects in the case in order to pursue an oil deal that would help close the country's deficit.

The government dismissed Nisman's charges and suggested the scandal involves a power struggle at Argentina's intelligence agency.

"They used him while he was alive and then they needed him dead," said Fernandez in a Facebook post, adding that his death was "sad and terrible". She did not say who killed him and no one has been arrested in the case, which has shocked Argentines and led to protests and theories about his death.


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