Legal Question in Criminal Law in Michigan

You haven't stated why he is threatening you. You should report him to the HR dept of your company, and perhaps file a police report and pursue a PPO if you truly feel threatened or that your life is in jeopardy.

Call the police!

I doubt that a "senior level manager of a security company" would be stupid enough to leave actionable evidence of threats on your voice mail.

There is usually a reason for managers leaving unpleasant messages on someone's voice mail, i.e. the recipient has an obligation to the manager or business that has not yet been resolved. Perhaps you should think of addressing this issue by answering his call instead of ducking it.