Ben Innes made global headlines after a picture of him with the EgyptAir hijacker surfaced last week. The image showed the 26-year-old grinning next to Seif Eddin Mustafa, who claimed to have smuggled a bomb belt on board, forcing the plane to redirect to Cyprus.
But the photograph has landed Mr Innes, from Leeds, in hot water as former students at York University claim he is a "convicted criminal".
Former students at the university, where he studied environmental science, claim they saw him attack a man during a university rugby club night out.
One witness, who did not want to be named, told The Mirror: "Ben has been hailed a champion of banter and Britishness, but he's a convicted criminal."