In the immediate aftermath of the downing of Malaysia Airlines Flight 17 over rebel-held, eastern Ukraine last year, Ukraine’s intelligence agency released what it said was audio from intercepted phone calls between separatist leaders and Russian military intelligence officers, in which the militants appeared to acknowledge shooting down a civilian plane by mistake.

Supporters of the rebellion, and officials in Moscow, disputed the authenticity of the recordings at the time, but the Russian-language audio, with English subtitles, was viewed hundreds of thousands of times on YouTube and convinced many in Ukraine and the West that the rebels were indeed to blame.