FILE - This file photo shows a portrait of Bolshevik revolutionary Leon Trotsky, founder of the Red Army, taken on Aug. 9, 1940, shortly before he was fatally attacked on Aug. 20, 1940, at his home in Mexico City. Once was seen as the most likely successor to Vladimir Lenin as the leader of the Soviet Union, Trotsky lost a power struggle with Josef Stalin and fled abroad. A Soviet agent attacked Trotsky in 1940 with an ice axe, mortally wounding him. (AP Photo/File)
FILE - In this Aug. 29, 2019 file photo, people carry the body of Zelimkhan Khangoshvili at his funeral in Georgia’s Pankisi Gorge valley. Khangoshvili fought Russian forces during a separatist war in the Chechnya region of southern Russia. After the war, he fled to Germany after surviving two assassination attempts but was shot to death in 2019 in Berlin. (AP Photo/Zurab Tsertsvadze, File)
FILE - Alexander Litvinenko, a former KGB spy and critic of Russian President Vladimir Putin, poses for photo at his home in London, on Friday, May 10, 2002. Litvinenko was seen as a traitor by the Kremlin after defecting from Russia in 2000 and fleeing to London. He was poisoned with tea laced with radioactive polonium-210 in a London hotel. On his deathbed, Litvinenko claimed Putin directly ordered his assassination. A British inquiry later found that Russian agents had killed Litvinenko, probably with Putin's approval. (AP Photo/Alistair Fuller, File)
FILE - This undated file photo shows Bulgarian journalist Georgi Markov, who defected to the West in 1969. Markov, a harsh critic of his country's pro-Moscow regime, died in 1978, four days after being jabbed in the thigh with a poison-tipped umbrella while waiting for a bus in London. (AP Photo/Dimitar Deinov, File)
FILE - Yulia Skripal poses during an interview in London on Wednesday, May 23, 2018. She and her father, Sergei Skripal, were found slumped on a bench in Salisbury, England, in March 2018. Sergei Skripal, a former spy, moved to Britain after being released from prison in Russia in a swap. British investigators said the Skripals had been poisoned with a Russian-developed nerve agent and blamed Moscow for the attack. Moscow denied the allegations. (Dylan Martinez/Pool via AP, File)
FILE - A man dressed in the uniform of the Ukrainian Insurgent Army and another with his face painted in colors of that army's flag hold a portrait of Stepan Bandera, at a rally marking the 67th anniversary of the anti-Soviet military unit in Kyiv, Ukraine, on Wednesday, Oct. 14, 2009. While living in exile in Munich in 1959, Bandera, 50, was killed after being confronted by a Soviet agent with a gun that sprayed cyanide. (AP Photo/Sergei Chuzavkov, File)
FILE - Sergei Skripal, left, is seen on a screen speaking to his lawyer from behind bars in Moscow on Aug. 9, 2006. Later released from prison in a spy swap, Skripal defected to Britain. He and his daughter, Yulia, were found slumped on a bench in Salisbury, England, in March 2018. British investigators said they had been poisoned with a Russian-developed nerve agent and blamed Moscow for the attack. Moscow denied the allegations. (AP Photo/Misha Japaridze)
FILE -- Russian defector Maksim Kuzminov attends a news conference in Kyiv, Ukraine, on Tuesday, Sept. 5, 2023, after flying a Russian army helicopter across the front line in Ukraine last year and defecting. Spanish police say his bullet-riddled body was found in a town in Spain. Sergei Naryshkin, head of Russia's foreign intelligence service, said Kuzminov became a "moral corpse" from the moment he planned his "dirty and terrible crime. (AP Photo/Vladyslav Musiienko, File)