According to Wilfried Huismann, he did. Lee Harvey Oswald was on Castro’s payroll. And JFK’s succesor knew about Castro’s involvement but because things were so politially volatile that any attempts to bring Castro to justice would result in a possible nuclear war which Lyndon B. Johnson did not want. I believe that in the wider interests of the world, this trail was not pursued to Cuba.
Read an interview with the German documentary filmmaker who has come up with this theory.