Buenos Aires: Argentine authorities can't locate the former spy chief at the centre of an investigation into the death of a prosecutor who had accused President Cristina Fernandez de Kirchner of an attempted cover-up.

Prosecutors accompanied by intelligence agents weren't able to find Antonio Stiuso at three addresses registered to his name, Intelligence Secretary Oscar Parrilli said. Mr Stiuso, who worked his way up through the intelligence agency over four decades before his recent departure last month, was summoned to testify on Thursday by the prosecutor investigating the death of Alberto Nisman from a shot to the head January 18.

A police officer stands guard in front of the prosecutor's, where a sign is posted about the staff mourning the death of Alberto Nisman. Credit:Rodrigo Abd

Ms Fernandez has accused Mr Stiuso of feeding Nisman with false information after the prosecutor prepared a 300-page report saying Ms Fernandez sought to cover up the alleged involvement of Iranian officials in the 1994 bombing of a Jewish community centre in Buenos Aires that killed 85 people. The government has lifted a confidentiality gag on Mr Stiuso if he's questioned by investigators, Mr Parrilli said today.

"The president wants the whole truth to be known and for Stiuso to tell everything," Mr Parrilli told reporters in Buenos Aires.

Nisman was found dead in his apartment a day before he was due to present his evidence to lawmakers. A draft document calling for the detention of Ms Fernandez and members of her government was found in Nisman's apartment following his death, prosecutor Viviana Fein said this week.

Bloomberg