Over 100 people died who were connected to the murder or knew possible suspects. That only fuels the conspiracy. Especially since it began with Oswald getting shot and then Ruby dying in custody before he could stand trial.
Yes, there are plenty of websites that deal with a lot of that info, someone mentioned McAdams and that is a good place to start. http://jfkassassination.net/home.htm
I would say in part, Oswald was a crackpot, bitter young man, pathological liar. Probably tried to shoot retired Lt. General Edwin Walker months before. He had the means and motivation.
But I don’t blame people for looking for a Conspiracy, it’s natural with the assassin being assassinated. I could be wrong but slowly over the years, I’ve moved to firmly believe Oswald was a lone-gunman, I could be wrong.