<human>: Can you condense the text into a few key points?

About 1.5 years ago I signed 1-year lease with a woman("Betty") on a condo I own. After the year was up, it automatically went to a month-to-month. Betty direct-deposited rent into my bank account. No issues, so I have not spoken to her in months.

A couple of weeks ago, I called to check in with her -- no urgent reason, but just wanted to make sure everything was in good repair. And see if she was planning to stay.  Phone number didn't work. I sent a letter. It was returned. Thought it might be a mistake, so I stopped by. Nobody was there. I slipped it under her door. 

I also sent an email to one of the neighbors to check in. Neighbor responds a couple of weeks later with a long email saying Betty's friends moved in a couple of months ago and Betty moved out. From my perspective, I have been getting paid rent by the new people (yay) but have no idea who they are and the neighbor says they yell, scream, slam doors, smoke pot, sell crack and have a dog that barks a lot. I have learned all of this in the past week and I want to figure out my options. 

Are these new people my tenants in a legal sense? I have been taking money from them in exchange for them living on my property, but I was not aware of where the money was coming from, since they have just been depositing it directly into my bank account for he past couple of months. Can I easily evict them? Do landlord/tenant laws (Alaska) even apply here? I have no proof they are selling or doing drugs (just the neighbor's email, but I don't think she is lying. Maybe exaggerating a bit or being gossipy.) I am probably going to contact a lawyer, but wanted to ask here first to help me prepare.
<bot>: My month-to-month tenant moved out without telling me and her friends moved in. They pay rent, but the neighbors hate them. What's the best legal way for me to get them out?