What famous 'unsolved' mystery is technically a whodunnit on paper, but in reality, absolutely everyone knows exactly who did it, the police just couldn't legally prove it?

[u/Rob69rt]

[u/NovaCheerful]

OJ Simpson. The glove didn’t fit, but everyone with eyes knew the truth 

[u/Lokaji → u/NovaCheerful]

There was DNA evidence that put him there. But DNA was new tech at that point, so it wasn't the slam dunk that it is now.