What do conspiracy theories suggest about the assassination of President John F. Kennedy, and what has been found to refute these theories?

Some believe that President Kennedy’s assassination in 1963 was orchestrated by a conspiracy involving multiple parties such as the CIA or the Mafia. They point to perceived inconsistencies in the investigation. However, investigations by the Warren Commission and the House Select Committee on Assassinations concluded that Lee Harvey Oswald acted alone. While there were some errors and inconsistencies in the investigations, no conclusive evidence has surfaced to support a broader conspiracy.