Is there anything I can do in this situation? Details inside.

I own a house in a nice quiet subdivision. My neighbors had to return to their hometown (in another country) due to a family emergency, so they put their house up for rent for a year contract. The renters moved in yesterday, and I’ve already noticed a few possible issues. The first being that my neighbor had assumed he was renting to a young man. A young man moved in, along with his young girlfriend and young kid, and 2 other young adults. We live fairly close to the university and college in the city, so I have a feeling the house next door might turn into party central. I don’t think any of them are over 20. But my main issue is their dog. It’s a pitbull. Now, I have nothing against pitbulls, but I know for a fact he is untrained and I have witnessed him bite his owner TWICE already, and she basically slapped him and tied him out in the backyard. Their backyard is not completely fenced off and it’s a flimsy rope. I have a chihuahua and a toy poodle. My backyard is completely fenced off and they cannot get out but I often tie my dogs in the front as the neighborhood kids like to come and play with them and they are well-tempered. I am very concerned about this dog… if it comes to a point when the dog gets out of hand, is there anything I can do? Also, just out of curiosity, could they not get into trouble by lying to the landlord about who is living there?