New tests back the theory that former Lebanese Prime Minister Rafiq Hariri was killed by a suicide truck bomb, investigators said in a report on Monday. The report from Belgian prosecutor Serge Brammertz s investigators said that Syria which had been accused of obstructing the investigation has been generally cooperative in its probe of the February 14, 2005 bombing that killed Hariri and 22 others. Investigators had long suspected that Hariri was killed by a bomb hidden in a Mitsubishi minivan and detonated by a suicide attacker. According to the report, new tests back the theory that a man either inside or just in front of the van detonated the bomb, which was probably about 1,800 kilograms. Bammertz s predecessor as chief of the investigation, Germany s Detlev Mehlis, had said the complexity of the attack suggested that Syrian and Lebanese intelligence agencies played a role in Hariri s murder. In Monday s report, Brammertz did not repeat Mehlis charge.