Libya had sought to question Muammar Gaddafi’s former oil boss in a corruption investigation before his body was found in the river Danube in Austria this week, Prosecutor General Abdelaziz Al-Hasadi told Reuters on Wednesday.He declined to discuss specifics of the probe involving Shokri Ghanem, who as head of the National Oil Corporation (NOC) ran the Libyan oil industry for years before defecting a year ago amid the uprising that toppled Gaddafi and moving to Vienna.His role made Ghanem, a former premier who was also close to Gaddafi’s son Saif al-Islam, privy to potentially damaging information, including on oil deals with Western governments and oil companies.Al-Hasadi would not confirm whether the investigation was related to Ghanem’s tenure atop the NOC from 2006.Libya "issued a warrant to bring him in. They only asked him to provide certain information, but this warrant is inactive on the international level,” he said, adding that such a warrant did not necessarily mean that Ghanem was to be arrested.Libyan authorities sent the warrant to Interpol around a month ago but had received "no decisive reply yet”, he added.Ghanem’s lawyer had been in touch about the request, he said. "Our request to bring him to Libya does not mean he is guilty, that is up to a court to decide,” Hasadi added.A passerby discovered Ghanem’s fully clothed body in the Danube early on Sunday, a few hundred metres (yards) from his home in a 22-storey apartment block.Austrian authorities say they have not detected foul play in the drowning, but friends and colleagues suspect enemies may have killed the man who knew more than anyone about the Libyan dictator’s billions.