BBC on the assassination of Georgi Markov
"Stefan Sverdlov, a colonel in the Bulgarian secret police until he defected in 1971, told the BBC in 1979: “Every department of the Darzhavna Sigurnost [Bulgarian secret service] is controlled by an advisor from the Russian KGB, sometimes known as an uncle, who reports directly to Moscow… It’s inconceivable that this could have been done without the Russians knowing about it.”
https://www.bbc.com/culture/article/20260904-the-poison-tipped-umbrella-that-pointed-to-a-kgb-murder
@istoria
"It would have benefited the Soviets in more than one way, as former KGB officer Khokhlov told the BBC in 1979 – beyond the physical death, it would have had a great psychological impact on dissenters abroad. “The fear that they’re not protected by distance, they’re not protected by the security systems of the West”, he said.
He continued: “The action is like coming behind someone and whispering in his ear, ‘We can get you any time we want. We can kill you.’”"