James Baldwin, Ray Bradbury, Albert Camus, Truman Capote, Charlie Chaplin, Ernest Hemingway, Langston Hughes, Gene Kelly, John Lennon, Dorothy Parker, Paul Robeson, Pete Seeger and Orson Welles all crossed the G-man's radar.
But Hoover's strangest suspect, without doubt, was French Existentialist Jean-Paul Sartre.
To find the answer, Hoover assigned a team of agents to spy on Sartre, who was visiting the US in April of that year at the Office of War Information's invitation.
Hoovers' agents applied routine FBI methods—surveillance, eavesdropping, wiretapping and theft—to find the answer. But the agents were stymied. One stole notebooks from Sartre's personal effects, only to inform Hoover "this material is all in French." Their findings, in the end, were inconclusive (a lot like Existentialism's).
Twenty years later, Hoover again focused on the philosopher, tagging him for a co-conspirator in JFK's assassination, because Sartre had belonged to the Fair Play for Cuba Committee, of which Lee Harvey Oswald was also a member. That investigation never quite panned out, either.
PHOTO CREDIT: Victor Romero (a tad suspicious himself).