Don't know if this is in the right section.This isn't out until next week but you can get your hands on the demo now.
Follow the instructions. You simply need to sign up to the website(precinct52) and input the four pieces of evidence.
The four pieces of evidence are:
Short cigarette (117b)
Coffee shop C (it says "diner")
117h (tyre tracks)
TIP: After you sign up it will say they will contact you soon about the four day challenge, ignore that, and click the link for Precinct52 again to input evidence.
Once done your code will appear on screen.
Once registered just sign in no need to confirm your e-mail addy as sometimes the screen may just go blank. This happened to me but it still registered me.
Be aware that it may take more than 1 attempt to get this and the site itself is quite slow but it's worth the wait. Also please note that this is only available to playstation 3 owners.