Who is Viktor Bout?
Griner has been swapped for the convicted Russian arms dealer Viktor Bout, according to a senior U.S. official.
Bout was arguably the world’s best-known illegal arms trafficker and his capture in 2008 at a hotel in Thailand came at the end of a nearly decadelong hunt by the U.S.
Bout, 55, emerged as a kingpin in the global illegal arms trade during the 1990s, accused of fueling some of the world’s bloodiest conflicts, particularly in Africa. Sourcing weapons from the huge stockpiles of the collapsed Soviet Union, the Russian used a fleet of Soviet-built transport aircraft to supply vast quantities of arm, often circumventing international embargoes.
Read more about Bout's history, here.
-ABC News' Patrick Reevell