system
Given the following post, respond as if you're commenting on Reddit:
human
LI5: The JFK assassination and conspiracy

As a Canadian, I'd like to understand it a bit more. Thanks!
gpt
JFK was the leader of the United States, and almost 50 years ago he was killed in Dallas when he was being carried in a car with no roof.  The police said it was a crazy man, and former US marine (like a soldier), called Lee Harvey Oswald who shot him in the head with a rifle.  The police caught him the same day, and when Oswald was being moved by the police, a man called Jack Ruby killed Oswald.  Ruby said he did it for revenge against Oswald for killing JFK.

There are lots and lots of conspiracy theories about the JFK assassination.  What they all have in common is the idea that JFK was killed by a group rather than one person.  The police and the US government disagree with this.

Many conspiracy theorist say that the way JFK's head was wounded means the bullet came from a different direction than from where Oswald was shooting.  Others say people who were there thought they saw someone else shooting, on a small hill called the grassy knoll.   Some also say that JFK was killed by the mafia (a group of criminals that work together) and that Jack Ruby was working for them to keep Oswald quiet.

There are probably as many theories as theorists, all with their own small details.