I just want to add a slightly different perspective here that hasn't been mentioned.
Make sure, for your own sake, before you turn them in, file a report, etc., that you think about what the repercussions for the other people will be. Make sure that you're okay with getting them fired. Yes, they loaded that gun and pointed it at their heads by making their comments, but it'll still be you pulling the trigger. I'm not saying you'd be wrong to do so--I'd probably do so myself in your situation. But you don't want to wake up in the middle of the night in a cold sweat two months later and think, "Wow, that guy is unemployed now because I got him fired. What did he tell his kids? Did this affect his marriage?" etc. Again, all of that stuff is 99% his fault, not yours--but at some point, you're probably going to forget that, and blame yourself for it, at least temporarily.
Now for all I know, the TM in question is 17 and there won't be any real repercussions for you to worry about. I'm just saying, think it through before you make any moves--even if it's the right move to make, you need to know that you're okay with all of the results. It may be better for your mental health to take a different approach, if it's possible and safe to do so. Just something to consider.