The key evidence that the Commission thinks could prove or disprove a deliberate act would be the Ndola airport’s radio traffic that night. The Commission reported “it is highly likely that the entirety of the local and regional Ndola radio traffic on the night of 17-18 September 1961 was tracked and recorded by the NSA, and possibly also by the CIA.”
The Commission filed a Freedom of Information request for any such evidence with the National Archives but did not appear hopeful that such records would be released unless pressure was brought to bear.