Mutassim Billah Gaddafi (Arabic: مُعْتَصِمٌ بِٱللهِ ٱلْقَذَّافِيّ‎, also transliterated as Moatassem or Al-Mu‍ '​tasim; 18 December 1974 – 20 October 2011) was a Libyan Army officer, and the National Security Advisor of Libya from 2008 until 2011. He was the fourth son of former Libyan leader Muammar Gaddafi, and a member of his father's inner circle. His mother was Safia Farkash. He was captured during the Battle of Sirte by anti-Gaddafi forces, and executed along with his father.