STORY: Griner, held since a week before the invasion of Ukraine, traveled from a Russian penal colony to Moscow, then to Abu Dhabi airport in the United Arab Emirates where the exchange took place, with the two walking past each other on the tarmac, U.S. officials said.

Described by the U.S. Department of Justice as one of the world's most prolific arms dealers who had sold weapons across the globe to terrorists and America's enemies for decades, Bout always denied the charges.