The Prisoner Swap
Bout is serving a 25-year jail sentence after his conviction in 2011 on four counts of conspiracy, including conspiring to kill American citizens. He is probably the highest-profile Russian in U.S. custody, and Russian officials have pressed for his return since his conviction.

The spokeswoman for the Russian Foreign Ministry said today that while negotiations on a deal were ongoing, “no concrete result has been achieved.”

A former officer in the Soviet Air Force, Bout was notorious among American intelligence officials, earning the nickname Merchant of Death as he evaded capture for years. His exploits helped inspire a 2005 film, “Lord of War,” that starred Nicolas Cage.

In 2008, he was taken into custody in Bangkok after being ensnared in a foreign sting operation run by the Drug Enforcement Administration. His extradition to the U.S., which Russian officials strenuously opposed, took more than two and a half years.