Unless there was a major life tragedy like an illness that prevented them from paying their bills, I say keep looking since it sounds like this is a desirable property

That is a tragedy.

Personally when it comes to any "niche list" you're dealing with some sort of a tragedy.

It offers greater flexibility, more competiveness, and less stress.For an example outside of business concerns:You have a family tragedy that requires funds.

Plus, if you set up LLCs then if some unforeseen tragedy occurs the two property's are separate and unrelated to each other so one could be lost while you still have the other.

However, this particular incident is a tragedy, hopefully no landlord here every has to deal with. 

One only has to look at the recent tragedies in California to understand the danger.Safety is an issue.

@Alex yes a real tragedy!  

The tragedy in Colorado is horrific, but, let's not over react.

I would probably not, I would definitely NOT renew her lease and if she was on a month to month rental I would give her notice to vacate with whatever lead time is required by your agreement, state or locality.Personally, I'd rather have a vacancy than a tenant created tragedy.