The United States played a significant role in the killings, supplying economic, technical and military aid to the Indonesian military when the killings began and providing "kill lists" (via the U.S. embassy in Jakarta) with the names of thousands of suspected high-ranking members of the PKI. A tribunal held in the Hague in 2016 concluded the massacres were crimes against humanity, and the U.S. backed the Indonesian military "knowing well that they were embarked upon a programme of mass killings". Declassified U.S. diplomatic cables released in 2017 corroborate this. According to UCLA historian Geoffrey B. Robinson, the Indonesian army's campaign of mass killings would not have occurred without the support of the U.S. and other powerful Western governments. Documentary filmmaker Joshua Oppenheimer, director of "The Act of Killing" and "The Look of Silence", said: