Read the story of what LBJ was doing on that day and his reaction - the piece I read has likely long disappeared - but the hit was not by the USSR,
Didn’t know that there had been a blame Russia angle to this. They are quite the scapegoat for the political classes in this country.
One thing we know for sure is that Lee Harvey Oswald was in repeated contact with the KGB. How this gets “meh” from all the conspiracy theorists is astonishing to me. Was LBJ tipped off by the KGB? Well, I need more proof than the claims of a lost internet article, but it’s easier to believe than the notion that the KGB didn’t do it.