Key dates related to the death of Argentine prosecutor Alberto Nisman, who was investigating the country's worst terrorist attack:

— Jan. 14, 2015: Nisman accuses then-President Cristina Fernandez of covering up the role of former Iranian officials who had been charged in the 1994 bombing of a Jewish community center that killed 85 people.

— Jan. 15, 2015: A congressional commission asks Nisman to present evidence of his accusations that Fernandez, Foreign Minister Hector Timerman and other senior officials brokered a cover-up in exchange for favorable deals on oil and other goods from Iran. Fernandez and Timerman denied the accusations. Iran denies involvement in the bombing.

— Jan. 18, 2015: Nisman is found dead in his apartment with a bullet in his right temple. A .22 caliber pistol is found next to him.

— Jan. 19, 2015: Investigating Prosecutor Viviana Fein tells reporters that the preliminary autopsy found "no intervention" of others in Nisman's death, but stops short of calling Nisman's death a suicide. Fernandez publishes a letter, lamenting Nisman's death and asking what "could have led him to take the terrible decision to take his own life."

— Jan. 22, 2015: Fernandez publishes a second letter saying that she's now convinced Nisman didn't commit suicide. She suggests a recently deposed senior intelligence agent, Antonio Stiuso, was involved in Nisman's death, but she does not elaborate on those allegations.

— Jan. 29, 2015: Nisman aide Diego Lagomarsino, a computer technician, says the prosecutor asked to borrow the death gun because he feared for his and his daughters' lives.

— Feb. 3, 2015: Investigators say they found a draft document Nisman wrote requesting the arrest of Fernandez. The document is dated in 2014.

— Feb. 10, 2015: A probe finds no traces of gun powder in Nisman's hands, but experts say it doesn't rule out that he fired the gun.

— Feb. 12, 2015: Nisman's ex-wife Sandra Arroyo Salgado, herself a judge, asks Congress to take the case to the Inter-American Commission on Human Rights.

— Feb. 26, 2015: Federal Judge Daniel Rafecas dismisses Nisman's allegations against Fernandez, saying the evidence fails to meet "the minimal conditions needed to launch a formal court investigation." An appeals court later upholds the dismissal.

— April 16, 2015: Fernandez's Cabinet chief Anibal Fernandez accuses Nisman of having used state money for a kickback scheme and to entertain women.

— Sept 7, 2015: The lead investigator in Nisman's death is sharply criticized after a video that shows police apparently failing to follow crime scene protocol in the apartment where Nisman was shot. Prosecutor Fein insists the crime scene had not been contaminated.

— Jan. 15, 2016: New President Mauricio Macri orders the declassification of files related to Nisman's death.

— March 19, 2016: Fein says for the first time that Nisman's death might have been an induced suicide.

— Sept. 21, 2016: Argentina's Supreme Court orders federal prosecutor Eduardo Taiano to take over the stalled case.

— Sept. 22, 2017: An investigation by Argentina's border police agency concludes that Nisman was murdered, contradicting earlier official findings that said that Nisman likely killed himself.

— Nov. 8, 2017: Taiano asks a judge to rule that Nisman was murdered rather than possibly committing suicide, and to order testimony by Lagomarsino.