Muammar Gaddafi:

A Misratan militia took Gaddafi prisoner, beating him, causing serious injuries; the events were filmed on a mobile phone. A video appears to picture Gaddafi being poked or stabbed in the rear end "with some kind of stick or knife" or possibly a bayonet. Pulled onto the front of a pick-up truck, he fell off as it drove away. His semi-naked, lifeless body was then placed into an ambulance and taken to Misrata; upon arrival, he was found to be dead. Official NTC accounts claimed that Gaddafi was caught in a cross-fire and died from his bullet wounds. Other eye-witness accounts claimed that rebels had fatally shot Gaddafi in the stomach; a rebel identifying himself as Senad el-Sadik el-Ureybi later claimed responsibility. Gaddafi's son Mutassim, who had also been among the convoy, was also captured, and found dead several hours later, most probably from an extrajudicial execution. Around 140 Gaddafi loyalists were rounded up from the convoy; tied up and abused, the corpses of 66 were found at the nearby Mahari Hotel, victims of extrajudicial execution. Libya's chief forensic pathologist, Dr. Othman al-Zintani, carried out the autopsies of Gaddafi, his son and Jabr in the days following their deaths; although the pathologist initially told the press that Gaddafi had died from a gunshot wound to the head, the autopsy report was not made public.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". What son of Gaddafi, present in the convoy, was found dead shortly after being captured?
Mutassim