(Reuters) – Russia’s Investigative Committee on Friday posted online a video of what it described as Ukrainian prisoners of war boarding a plane that later crashed in the south of the country. But Ukrainian commentators immediately cast doubt on the authenticity of the video. Moscow accuses Kyiv of downing the plane on Wednesday in Russia’s Belgorod region and killing 74 people on board, including 65 captured Ukrainian soldiers en route to be swapped for Russian PoWs. The committee, Russia’s main investigative authority, posted the video on its Telegram channel showing vehicles approaching an …