Letter dated 21 December 2016 from the Secretary-General addressed to the President of the Security Council; Summary by the Secretary-General of the report of the United Nations Headquarters Board of Inquiry into the incident involving a relief operation to Urum al-Kubra, Syrian Arab Republic, on 19 September 2016 [S/2016/1093]

https://www.ecoi.net/en/file/local/1224597/1226_1483017934_n1645820.pdf