Justice Minister Carlo Nordio's Chief of Staff Giusy Bartolozzi has been put under investigation by the Rome prosecutor's office in relation to Italy's release earlier this year of a Libyan general wanted for war crimes, sources said on Tuesday.

The case regards Njeem Osama Almasri, who was arrested on an International Criminal Court (ICC) warrant at a hotel in Turin at dawn on January 19 and was returned to Tripoli on a State flight following his release on a technicality by a Rome appeals court on January 21.

Almasri, the head of Libya's judicial police, is accused of torture, rape and murder in relation to his management of a detention centre in Tripoli.

His release was ordered after Nordio did not respond to the Rome appeals court's request to back the arrest.

The Tribunal of Ministers alleges that Almasri was released because the officials feared there could be reprisals against Italian citizens and interests in Libya if he were handed over to the ICC.