Alexander Litvinenko, a former Russian intelligence officer, died in London weeks after drinking tea that was later found to have been laced with the deadly radioactive compound polonium-210.
Sergey Naryshkin, who has been on a U.S. Treasury Department sanctions list since 2014, reportedly met with U.S. Director of National Intelligence Dan Coats and other U.S. intelligence officials.
"What we're talking about is the new concept of so-called hybrid war, which a government wages but won't admit to," Gennady Gudkov, a retired KGB colonel, tells NPR. "It's extremely hard to prove."
Luke Harding, the former Moscow Bureau Chief for The Guardian, saysthat Putin "wants to turn the clock back to an age ... where strong sovereign nations didn't talk about values or human rights."
Opponents of Russian President Vladimir Putin and former colleagues who have fallen from favor seem to be dying at an unusual rate. Russia-watchers believe the deaths are not random.
Soviet-era movie stars, cosmonauts and, yes, intelligence agents once socialized at Aragvi over chicken tabaka and Georgian wine. Now the restaurant has reopened for regular diners.
Vyacheslav Trubnikov was a Soviet and Russian spy for more than three decades. He found some of his American adversaries worthy rivals. Others, not so much.