At my building we have a preloader who is also an air driver. Before he was an air driver he was a helper. He has a long history of drug use (he has been sober for 5 years now but will mention his past from time to time) and is extremely tightly wound. He's been my helper a decent amount and right away I could tell he had an anger issue. A serious one. Me and another helper have discussed it before and both agree he seems like the type of guy that would perform a shooting like the one in Birmingham. Wouldn't surprise me at all. I've wanted to tell someone but had nothing to tell management besides telling them he has an anger problem and they wouldn't do anything about it. Well, I was just told by the other helper that last week the guy with the anger problem got into an argument with someone else on the preload and made a threat about coming in with a gun and shooting people. He made the threat almost under his breath and only one person heard it. Who should I tell the other preloader to inform about this? Center manager? Supervisor?