Since your previous tenant has abandoned the property and this new person is a complete stranger, with no lease, it sounds like an unlawful detainer case which I've found is quicker than an eviction.

It's not worth the risk of unlawful offset.Having said that, congratulations on having (extremely) long-term tenants and on their departure.

The complaints grew and I had no choice but to file an "Unlawful Detainer" eviction.Since then things have become worse.

The legal process for dealing with criminal actions or violations of civil law is not speedy and more often that not in this type of eviction situation, you'll be dealing with someone who is "judgement proof" so even if they are (eventually) punished for a criminal action, you're unlikely to ever be made whole.

@Doug JohnsonI would never do such an arrangement I would charge a tenant if they left early .that is punishable I would certainly not allow their personal situation or family member issues dictate our agreement that was made .

Tell him that he has put you at serious risk by using your property in an unlawful manner with drug use on the premises and the discharge of a weapon. 

If she doesn't leave, then evict her for unlawful detainer.

Have you ever been evicted (unlawful detainer)?"

It's a five bedroom house and I am not sure if this property falls under Philadelphia's educational housing district which will make it unlawful to have more than 3 strangers living together.

This pretty much breaks every single rule in our ethics code and is unlawful so she would definitely at minimum at get in trouble with her broker if not actually get fired because she represents a large liability to the brokerage as the Broker himself is risking his license to be able to supervise her.