Buenos Aires: Forensic experts have found DNA evidence of a second person in the apartment where an Argentine prosecutor was found dead last month after he accused the president of whitewashing a deadly 1994 bombing.

Investigators hope the new DNA sample will shed light on a case that has spawned conspiracy theories involving President Cristina Fernandez, rogue intelligence agents and a group of Iranians accused by the Argentine courts of bombing the AMIA Jewish community centre 21 years ago.

Prosecutor Alberto Nisman was to give evidence against the president the next day. Credit:AP

The body of prosecutor Alberto Nisman was found in his bathroom on January 18, a bullet in his head and a pistol by his side. He had been scheduled to bring a case to Congress the next day accusing Fernandez of trying to derail the criminal investigation into the bombing that killed 85 people.

Until Tuesday there had been no evidence of anyone else in Nisman's Buenos Aires apartment. The judge in the case filed court papers saying a sample "corresponding to a genetic profile different from Nisman's" had been found.