Another attempt at Castro's life was by way of a fountain pen loaded with the poison Black Leaf 40 and passed to a Cuban asset in Paris the day of President Kennedy's assassination, November 22, 1963. Notably, the evidence also indicates that these two events occurred simultaneously, in the same moment.[68][69] Rolando Cubela, the potential assassin, contests this account, saying Black Leaf 40 was not in the pen. U.S. Intelligence later responded to say that Black Leaf 40 was merely a suggestion, but Cubela thought that there were other poisons that would be much more effective.