Well, as a guy this is sorta wierd for me to be commenting on this subject. But, people lie, just remember. You can't believe everything someone tells you, especially over the net lol.
Chat lines, and msn are full of lies. Not always, and most of the time people are telling the truth. But I know some people that tell lies just to get attention, or to get well... in someone's pants.
If they had 115 detentions, i wouldn't doubt that they have a temper.
If they have had 115 detentions, and smoke, and have had sex... i wouldn't doubt that they do drugs too.
I'm around this stuff all the time.
Really its up to you if you want to date them. There are probably some risks involving dating this guy. I suggest you get to know him a bit better, hang out with him a bit more, see what he's really like.