This could help weed out any of the unscrupulous folks who could easily disappear into the woodwork if a problem arises.

She made stupid threats like 'I'm going to get her father involved.' 

In my books this is a straight up threat and I do not tolerate tenants threatening me.

The threats to my life.

let them direct their threats to the lawyer he'll tell you the ones to worry about. 

Savvy tenants aren't going to just believe you when you say it will be cleaned and painted and in pristine condition and available on the day it's supposed to be - when they are stepping over someone dirty laundry.And, they won't feel comfortable looking inside closets or the garage, etc.And, there's the potential liability of your current tenant claiming some expensive jewelry disappeared during your walk-throughs.I know the idea of having to eat a month's rent in-between tenants hurts, but I truly believe you get better tenants, who will not be as likely to cost you in problems, if you clear out the last one, get the unit in beautiful show condition, then start showing it.  

This is one of those vague threats of taking action against you if you attempt to enforce your rights.Any one of these I would let slide on its own, but taken together, this is a pattern of behavior that will not improve with age.First thing I would do is offer to release them from the lease because of the concern they recorded over the rain findings without penalty for early termination.

We have video footage of death threats, proof from department of public works, plumbers, board of health, and other contractors backing every single thing up I have stated.We of course will screen better next time, but first we need to get her out, which seems impossible right now.

John: you should have your management company video/photo the apartment asap to document in case the tenants make true on their threats to damage your property.   

The other allegations are not factual.Then, Mr Reynal sends me emails insisting that I buy his duplex back for 20k more than I sold it to him for under the threat of impending legal action.