Four UN staffers might have been killed last year by "friendly fire" from Afghan security forces responding to an insurgent attack in Kabul, according to a United Nations inquiry revealed on Monday.

　　The UN report describes a confusing chain of events on Oct. 28, 2009 when insurgents dressed as Afghan police attacked the privately-run Bakhtar guest house, where 34 UN employees were staying.

　　The four-member board of inquiry, headed by Australia's former senior federal police official Andrew Hughes, has released the report to UN Secretary-General Ban Ki-moon, who called on Afghan authorities to follow up with their own investigation.

　　American Louis Maxwell, a security officer at the guesthouse, "may have been killed by Afghan security forces who may have mistaken him for an insurgent," said UN spokesperson Martin Nesirky. "The report was not able to determine who fired the shots that killed the three other United Nations staff members though it leaves open the possibility that they also may have been killed by friendly fire."

　　Susana Malcorra, under-secretary-general for Field Support at the Department of Peacekeeping Operations, described the insurgent attack and the following events as "a very confusing situation" where it was not clear who was attacking whom.

　　At roughly 5:30 a.m. local time on Oct. 28, 2009, insurgents dressed in Afghan police uniforms attacked the Bakhtar guest house with Ak-47s and grenades. An explosion ignited a blazing fire, which killed one UN staffer, Malcorra told reporters.

　　Four UN staff members, including Maxwell, then ran through the guest house and out the back door, but three of them were killed by AK-47 bullet wounds that appear to have been fired by Afghan security officers, who were waiting outside.

　　It seems that Afghan security forces believed the three UN staffers and Maxwell were insurgents, said Malcorra.

　　Maxwell was later seen on the roof of the guesthouse. He then fell. The reason is not understood.

　　An amateur video of the attack seen by UN officials, the Federal Bureau of Investigation (FBI) and Stern magazine appear to show Afghan police surrounded the fallen Maxwell, who was then repeatedly shot at close range.

　　Malcorra confirmed that the person in the video was Maxwell. However, she repeatedly stated that forensic analysis concluded that Maxwell was shot from long-range distance, which would seem to contradict the video footage.

　　"Forensic evidence concluded he died from a long-distance shot, "she said.

　　By the time the incident was over, it was 7 a.m. local time.

　　A number of questions remain unanswered, said Malcorra, including the sequence of events.

　　"The timeline was one of the biggest challenges and there were some pieces that were not able to be fully put together," she said.

　　However, one lesson that has become apparent from the report, she said, is the lack of UN security officers who speak the local language, which only added to the confusion.

　　"Some of the exchanges of communications took place at a certain level but did not trickle down to the operational level that is needed," she said.

　　In light of the seriousness of the incident, the secretary- general will send top UN safety and security official Gregory Starr to Kabul next week to discuss next steps and follow-up with the Afghan authorities, said Nesirky.

　　Ban has also instructed UN peacekeeping chief Alain Le Roy and UN special envoy to Afghanistan Staffan de Mistura to contact relevant NATO officials for further consultations on how to improve cooperation in the event of future emergencies, he added.

　　"The secretary-general reiterates the UN's commitment to transparency and the strengthening of security for its personnel serving in dangerous locations," said Nesirky. "He calls on the Afghan authorities to ensure a thorough investigation into the attack on the guesthouse and the killing of UN staff."

　　The board of inquiry began its work in February and traveled to Kabul the same month. The report, which will not be made entirely public, was shared with Malcorra last Wednesday. The relevant findings have been shared with the Afghan authorities and other stakeholders, including the FBI.