He told the HR manager that I have been harassing him online and making threatening and violent comments against him.

I am trying to be civil about this matter but tenant is threatening going legal because of the Pm taking awhile to remedy the repairs and the mold.

All they did was send a letter to the building/business owners threatening action, and they all shut down. 

Photos if necessary, if he verbally threaten you, while you are at the property, call police immediately so they respond and can take a report. so you have it documented. 

I might add that you should install surveillance cameras in case he comes back and does damage to the property or threatens you etc.

I would recommend more caution with threatening the borrower or pulling the plug.

If you spend more than three weeks on it, and have threatened to report them to the CFPB, and they aren't budging even with that threat... that probably means someone needs to pay their damn bills.

I've actually see illegal activities and had to threaten legal action against the agent and his broker.

Now enter the hysterical tenant who emails me everything that the plumber told her, who is basically threatening to move if I don't address this immediately. 

I'd say too, the best defense is a good offense, once threatened go into action as if it were war!