There's a very fine line about what you can and cannot disclose. If your company has a lawyer on retainer, you could check with her/him, but the risk of liability is high.
Of course I agree that this jerk deserves to be outed, but not only did I formerly work with lawyers, I also checked references for a "large national insurance company" and the rules have tightened significantly since then.
Really, I'm just trying to cover your @ss. The hell you would face in court if a lawsuit is indeed instigated is worse than the @ss-kicking this guy deserves.
I'm sorry things work this way, but they do.