Belgian prosecutor Serge Brammertz will stay on as chief investigator of the UN commission probing the assassination of former Lebanese Prime Minister Rafik Hariri until December 31, the United Nations announced Monday. Secretary-General Ban Ki-moon informed the Security Council on Friday that he intends to extend Brammertz's appointment until the end of the year, UN spokeswoman Michele Montas said. His appointment was due to expire at the end of June. The suicide truck bombing that killed Hariri and 22 others in Beirut in February 2005 sparked huge protests against Syria, which was widely seen as culpable. Syria denied involvement but was forced to withdraw its troops from Lebanon, ending a 29-year presence.