Shortly after his conviction in 2011 on charges including conspiring to kill American citizens, the Russian arms dealer Viktor Bout relayed a defiant message through his lawyer, even though he faced the prospect of decades in prison.
Mr. Bout, his lawyer said, “believes this is not the end.”
More than a decade later, Mr. Bout, 55, may be nearing a chance for a new beginning even though he has served less than half of his 25-year prison sentence.
The United States, trying to negotiate the release of two Americans imprisoned in Russia — the basketball star Brittney Griner and the former Marine Paul Whelan — last month proposed exchanging them for Mr. Bout, according to a person briefed on the negotiations.
Secretary of State Antony J. Blinken declined to discuss details of a possible swap on Wednesday, but said that the United States had made “a substantial proposal.” He said he expected to raise the issue in the coming days with his Russian counterpart, Foreign Minister Sergei Lavrov.
Russian officials have pressed for Mr. Bout’s return since his conviction in 2011 by a New York jury on four counts of conspiracy that included conspiring to kill American citizens. Prosecutors said he had agreed to sell antiaircraft weapons to drug enforcement informants who were posing as arms buyers for the Revolutionary Armed Forces of Colombia.
The attorney general at the time, Eric Holder, called him “one of the world’s most prolific arms dealers.” Now, he is probably the highest profile Russian in U.S. custody.
Mr. Bout (pronounced “Boot”) had become 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 as a character named Yuri Orlov.
Mr. Bout grew up in Dushanbe, Tajikistan, until his conscription into the Soviet military at age 18. After a term in the Army, he studied Portuguese at the Military Institute of Foreign Languages in Moscow, a common entree to Russian intelligence services, and eventually became an officer in the Air Force.
The Soviet Union disintegrated not long after Mr. Bout left the military. As Russia’s economy collapsed and criminal groups thrived, he moved to the United Arab Emirates and started a cargo company that grew to a fleet of 60 planes.
With military supplies of former Soviet states leaking onto the black market, his shipping empire delivered guns to rebels, militants and terrorists around the world, prosecutors said.
Mr. Bout was accused of selling weapons to Al Qaeda, the Taliban and militants in Rwanda. According to United Nations investigations, he flouted arms embargoes in Sierra Leone, The Democratic Republic of Congo and Algeria, where he sold weapons to both the government forces and the rebels fighting them.
U.S. authorities finally caught up with him in Bangkok in 2008. Mr. Bout met with undercover Drug Enforcement Administration agents he believed represented rebels from Colombia’s Revolutionary Armed Forces, or FARC, which the United States considered a terrorist organization until last year.
When the prospective buyers told him the weapons could be used to kill American pilots, Mr. Bout responded, “We have the same enemy,” prosecutors said.
Thai authorities arrested him on the spot. He was extradited to the U.S. in 2010 and two years later was sentenced to 25 years.
Ivan Nechepurenko contributed reporting.