(CNN)Diego Lagomarsino is among the few who can offer clues about the puzzling death of Argentine prosecutor Alberto Nisman. The IT security expert was one of the last to see Nisman alive. Nisman was found dead in his apartment days after filing a report accusing the country's top leaders of covering up Iran's involvement in Argentina's worst terrorist attack. It looked like a suicide, but now even the government has doubts that is the truth. So when Lagomarsino decided to address reporters on Wednesday, it should have been an unequivocally illuminating event. But like so much of the information surrounding Nisman's mysterious death, seeds of doubt had already been planted.
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The owner of the gun that killed Alberto Nisman explains his side of the story
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Diego Lagomarsino gives new details about Nisman's puzzling death
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He is also the only person charged in connection with the death
The gun that @placeholder had given him was near the body, along with a shell casing.