Oswarld was the shooter and lone shooter, but I wouldn't be surprised that there was a well oiled Soviet operation behind him. Also his killer, Jack Ruby, died in fairly suspicious circumstances just four years later in prison: his cancer seemed atypically malignant with very severe growths in many of his organs, and I wonder if he was taken out by the KGB/GRU in a similar manner to how the FSB murdered Alexander Litvinenko with a radioactive isotope.