The whole thing stinks to high heaven but I believe that Oswald did act alone.
Now it would not surprise me if he was part of a larger group, maybe Cubans, maybe the mafia.
The one thing I think the media has done a poor job on is Jack Ruby. I once knew a guy who knew Ruby very well. The one thing he was sure of was that Ruby was much heavier into organized crime than has been admitted.
Still after all is said and done, I think Oswald acted alone.
Seems more likely....
info on jack ruby here.
http://jfkfacts.org/assassination/news/ex-flame-says-jack-ruby-had-no-choice-but-to-kill-oswald/