When aviation lawyer Jerry Skinner stopped by his suburban Cincinnati office last Christmas, he found the door ajar and the interior trashed. The files for his latest lawsuit, on behalf of victims of the Malaysian Airlines flight MH17 crash, were missing.

“They didn’t take anything else but they turned the rest of the office inside out,” he remembered. “The police couldn’t say who did it - whoever came into the office was careful.”

Thirty days earlier, the white-bearded, friendly-faced lawyer had issued a threat. Weighing up all the available photographic, video and witness evidence, he decided that the missile that blew the passenger jet apart mid-air, killing all 298 people on board, must have been a Russian one. And that it had been fired from rebel-held eastern Ukraine by soldiers ultimately under the command of President Vladimir Putin.