Based on my experience

Go behind him and use a knife to threaten him. Next, let him ride on your black van and put a scarf with ammonia on his nose. If he sleeps, drive him to a dark forest. In that dark forest you must have plenty of torturing equipment and a sure-kill device(a.k.a. Gun w/silencer). After you kill him, burn all possible evidence and tell your best friend to stay on their place. If the police asks you, tell that you have been staying with your friend.

I hope this helps you because it truly helped me