According to counsel in Leviticus you should stone him outside the city gates...if you don't live in a city it really throws a wrench into things though...maybe you could buy a lamb or young bull...a firstling of course not lame or sumpin and offer it up as a sin attonement on his behalf...the stoning does sound more sporting but do it quickly incase he makes a run for a city of refuge or something cowardly like that.
Why would you ask about turning in your friend unless he was in physical danger or something..is he underage? Was he doing crack or crystal meth?...or was he just having fun at a dance?