Even if he had been found not guilty, this is not what the OP was looking for.
It’s asking for big not tall.
The question is so open that you could get a variety of different answers. Many people were found “not guilty” of some crimes but later guilty of others.
However, for the purpose of a nomination I would go for Wyatt Earp. Mainly because he is often considered a hero of the old west but was often little more than a thug. The gunfight at the O.K. Corral is a pretty dark affair.
Nixon.
When was Nixon tried in a court of law?
bill clinton
Apparently people can’t or won’t read the OP, or have some kind of political axe to grind.
And Cullen Davis is one case that’s always been jarring. http://www.trutv.com/library/crime/notorious_murders/not_guilty/t_cullen_davis/index.html
The question is like asking “which black objects are actually white?”. The only answer is “that’s a dumb question.”
The justice system is how we determine guilt or innocence, so it’s pronouncement is the only one that matters. The only people who can gainsay its pronouncement are those who actually witnessed the accusaed commit the crime in an unimpeachable way–everyone else simply must accept the court’s verdict because that is all we have to go on.
Maybe they’re referring to his size. Or [woo woo]Vince Foster[/woo]
No, what determines someone’s guilt or innocence is whether they’re guilty or innocent. The criminal justice system is obviously the normal way of trying to find that out, but a court declaring someone “guilty” or “not guilty” doesn’t actually make them guilty or innocent.
And that’s before we even get onto the “not proven” verdict! 
Technically, true–Congress had nopt sat to impeach.
Ollie North?
I disagree. A person can be found not guilty in a court of law because there wasn’t sufficient evidence to convict him. That’s a sound principle of justice. But just because the state didn’t find a person guilty in court doesn’t mean he can’t be considered guilty in public opinion.
But all consequences flow from what the court says, not what anyone else thinks. So, you can posit the existence of this realm of “actually guilty” or “actually innocent” if you want to, but absolutely no consequences flow from the existence of that realm, so it may as well not exist.
That’s true enough, but it doesn’t contradict anything I said.
I wonder how often this will have to be rewritten to express the meaning of the OP without the nitpicking:
“Who is the most infamous individual to have been tried in a court of law for a crime which he or she actually did commit (either according to popular public opinion or based on facts gleaned later) but who was not convicted for that crime?”
Here’s the way to express it to avoid my nitpick: Which individual is most thought by public opinion to have committed a crime even though he was not convicted in a court of law?
It avoids problems with “actually did commit” presented by your version. The courts are how we determine whether someone actually did commit a crime–what they say is the truth (for all people other than those who have actual first-hand unimpeachable evidence to the contrary).
Even when they later confess? Do you really think history books ought to hedge on whether or not J. W. Milam and Roy Bryant killed Emmett Till?
Sure it does. You claimed the only way a person can be considered guilty is if they are found guilty in a court of law. I feel that there are alternative ways for a person to be considered guilty.
Which is irrelevant. The Senate sitting for an impeachment trial is not a court of law and impeachment is not a criminal proceeding.
Do you think everyone that confesses to a crime should be considered automatically guilty of it?
You are illustrating my point you can consider anyone guilty of anything for any reason you want to. But as a society, we have created a justice system to determine guilt or innocence, and it is that determination that carries consequences, not yours.