Look for a Property Owners Association or a local Apartment Association. Even though you are renting a house these Associations have resources that can assist you in dealing with the situation.
You probably will need a Lawyer, make sure that they specialize in evictions. Also, I would put some pressure on the agency that rented the house for you, after all, they bear responsibility in this.
Some lawyers offer free consultations, you may try consulting one without any cost to you and get some advice even if it is minimal, it can be useful. Last of all, try not to be intimidated or afraid of these people. It's your home and while they have some rights, you are the one in charge of your property, not them.
I hope this will be of some help to you. I am certified in California as a Residential Property Manager. I am not familiar with Eviction Law in your state but the internet has some good resources for property owners in their respective states.
Good luck with your tenants from hell. I just got rid of some that I had rented to in May. What a relief since they left.