Robert F. Kennedy's assassination in 1968 seems like it should be an open-and-shut case. Many people crowded in the small room at Los Angeles's famed Ambassador Hotel that fateful night saw Sirhan Sirhan pull the trigger. Sirhan was also convicted of the crime and still languishes in jail with a life sentence. However, conspiracy theorists have jumped on inconsistencies in the eyewitness testimony and alleged anomalies in the forensic evidence to...