One of the suspects in the assassination of a former Lebanese prime minister has been arrested in Dubai, an Arab diplomat said. Purported Syrian intelligence officer Mohammed Zuhair Siddiq was named a suspect by a UN commission investigating the 2005 assassination. Former Lebanese Prime Minister Rafik Hariri was killed in a truck bombing that many Lebanese believe was carried out by the country's long dominant neighbor Syria. Syria denies involvement. Initially Siddiq was a witness who gave evidence to UN investigators. His information, however, was later discredited, and at the UN commission's recommendation, he was arrested in France in October 2005 as a suspect in the murder. He disappeared from house arrest in France in March 2008, according to French authorities. The United Arab Emirates' Foreign Ministry could not confirm he was living in the country and did not know if he was arrested. The Arab diplomat said he was arrested Friday in Dubai and that Syria has requested his extradition. The diplomat spoke on condition of anonymity because of the sensitivity of the case. Syrian media reports have said Siddiq is wanted there for allegedly giving false testimony implicating Syria in the assassination. Only four other suspects in the killing are in custody. They are pro-Syria generals who led Lebanon's police, intelligence service and an elite army unit at the time of the assassination. They have not been formally charged. An international tribunal in the Netherlands took up the case in February.