ISLAMABAD- A six-member preparatory delegation of the UN Commission investigating the assassination of late Prime Minister Benazir Bhutto arrived here Tuesday on a two-day official visit. Headed by Mark Quarterman, the preparatory UN team will prepare a review report about technical and security assistance for central investigative commission that is expected to visit Pakistan next month. The delegation that would likely visit the place of murder and meet the officials of police and other law enforcement agencies comprises political experts, legal experts, field support staff and consultants. PPP Chairperson Benazir Bhutto was assassinated on December 27, 2007 at Liaquat Bagh, Rawalpindi, shortly after addressing a partys election rally. Apart from a Pakistani investigation team set up by the then government, investigators from the Scotland Yard also visited Pakistan and assisted the Pakistani team. Meanwhile, Senator Safdar Abassi, one of the closest friends of Benazir Bhutto and central PPPP leader, has said that twin attacks on Benazir Bhutto on October 18 and the fatalistic one on December 27, were interlinked in a single chain of events. He demanded of the government to step up investigations in the light of the FIR lodged against the first attack that occurred on October 18, and demanded strict investigation regarding immediate washing of the crime scene in Rawalpindi. Online Adds: While strongly advocating findings regarding the motives, and financing of the murderous attacks on Benazir Bhutto, he demanded inclusion of names of personalities such as Gen Hameed Gul, Chaudhry Pervez Elahi and others indicted in a memorandum by late Benazir Bhutto.