Argentine President Cristina Fernandez says she's "convinced" prosecutor Alberto Nisman did not commit suicide.

In a letter published Thursday by state news agency Telam, Fernandez says all the questions about Nisman's death "have been converted into certainty. The suicide (I'm convinced) was not a suicide."

Fernandez' letter contrasts with the one she wrote Monday saying she believed Nisman took his life.

The 51-year-old Nisman was found slumped in the bathroom of his apartment Sunday night with a bullet wound in his head.

Four days before Nisman gave a judge a 289-page report alleging Fernandez secretly reached a deal to prevent prosecution of former Iranian officials accused of involvement in the 1994 car bombing of Argentina's largest Jewish center.

Fernandez dismissed those accusations in Thursday's letter.