Just a bit of history
https://www.usatoday.com/story/news/politics/2018/01/10/jfk-files-kgb-had-trusted-relationship-longtime-warren-commission-critic-mark-lane/1018691001/
Beyond informing on Lane, Shamrock told the CIA and FBI that the Soviet leadership was upset about Kennedy’s assassination, which “was a great loss, not only for the United States and the Soviet Union, but for the whole world,” Branigan wrote Sullivan on April 4, 1967.
“According to Shamrock, the Soviets felt that they could trust President Kennedy and could deal with him on a cooperative basis," Branigan wrote. "Shamrock further stated that the Soviets mourned President Kennedy’s death, a situation which Shamrock considered very unique inasmuch as the person being mourned was the leader of another country.”
…
…
Shamrock’s information showed the Soviets were prone to believing some of the conspiracy theories surrounding the Kennedy assassination.
As a result of long KGB study, “the KGB concluded that President Kennedy was killed by representatives of a group of monopolists, characterized as the military-industrial complex in the United States,” Branigan wrote to Sullivan. “The KGB felt that President Kennedy had tried to limit the activities of this group of monopolists and therefore they planned his assassination.”
Folks knew back then it appears…