UNITED NATIONS - The UN commission of inquiry into the assassination of former Prime Minister Benazir Bhutto will make a contribution to cause of justice by identifying the facts and circumstances behind the December 2007 tragedy, its head Heraldo Munoz said on Wednesday. Responding to Press criticism in Pakistan that the three-members commissions mandate is too narrow or limited, he said, 'well contribute to justice and justice has to be made by the Pakistani authorities. Munoz, who is Chiles UN Ambassador, told reporters that the commissions mandate was agreed between the UN and the Government of Pakistan and was indeed limited. The mandate of the commission is to look into the facts and circumstances of the assassination, and the responsibility for investigating the crime and prosecuting the perpetrators remains with the Pakistani authorities. The Chairman and the two other members of the commission Indonesian Attorney General Marzuki Darusman and Irelands former Deputy Police Commissioner Peter Fitzgerald returned to New York over the weekend after a week-long visit to Pakistan. The Commission, which began its work on July 1, will submit a report to Secy-Gen Ban Ki-moon within six months, he said. Ban will then share the report with the govt and submit it to the Security Council for information. The Chairman said that the commission was receiving good cooperation from the Government of Pakistan, especially the Ministry of Interior. He said they hope to work closely with the govt in determining the facts of the murder. 'We have a lot of hard work ahead of us, Munoz said, adding, the commission would work with the Pakistan govt in determining the truth. A technical team for the commission is staying back in Pakistan to carrying forward their work. The Pakistani govt had requested the UN to establish a commission to investigate the Ms. Bhuttos killing. It has already paid 1.8 million dollars to the UN as seed money to cover its initial costs, and more countries are likely to contribute. Benazir Bhutto was assassinated in gunshot and suicide bombing attacks on Dec. 27, 2007 after addressing an election rally at Liaquat Bagh in Rawalpindi.