According to highly respectable site Gamepolitics, an early European version of Manhunt 2
was leaked last week.
The big issue is that this is an older, AO caliber beta, before the game was hacked down to a less grisly M rating. It's a PS2 build, and supposedly some crafty people have already torrented the image, burned it onto a disc and gotten it to work. I'm betting that it's an inside job, a lower level tester who was mad about the game being edited and decided to leak it. I wouldn't be surprised if someone at Rockstar loses their job over this, but the bigger problem is the potential media fallout. This game is already being demonized like crazy, and this unfortunate slip will only add more fuel to the PR nightmare fire.
I'm just interested to see how much of the game was edited--that'll give us an idea of whether or not the whole AO debacle was a subtle Rockstar publicity stunt.