Interesting plot for a teen novel?

One Julius Ceaser was murdered by a group of people stabbed to death so you can't write something about him being killed by one person you can't change history like that. Also could you do something more exciting then snails? The thing is it's miss leading if you say no one knows who killed him when a group of citizens killed him. He was also killed somewhere else. Even if it fiction you should get those things right.