Dear Mayja, How do you know that it was the FBI that assasinated JFK? I always understood it to be the CIA(for which, by the way, there is a significant amount of evidence).
A real Christian is someone who believes the Bible and has faith in the sacrifice of Jesus Christ which is the only thing that can save you. Good works can not save anybody. Go to the topic here on Armenian Evangelicals to learn more about it. that is a really good article.