some of the theories that are out there. >> several thousand enthusiastic -- >> nearly 54 years since the day president john f. kennedy died and conspiracy theories difficult abound. >> the truth is oswald killed the president. >> os wal, as in lee harvey os wal of the the federal government says he shot the president and only him. despite that, conspiracy theorists just don't buy it. they point to people like the man who came to be known as umbrella man. he was seen opening and closing his umbrella on the grassy noel on a perfectly sunny day. some have argued that the man was either signaling a shooter or shooting a poison dart at the president. >> the umbrella man came forward. he testified before congress. there was never any credible evidence. >> could bring down the most powerful man in the world. there must have been a more