Neighbor threw coffee on our windshield

Our neighbors fight all the time. Like as in the woman hits her man and he yells at her. They are in and out the apartment building screaming constantly. For some reason the woman really doesn't like me. She gives me dirty looks constantly and I'm not sure why. The only thing I can think of is that she thinks I just "bounced back" after having a baby(she had a baby and still has some weight on her) even though I've worked SO DAMN HARD to get here and I'm still 20 lbs overweight. The only reason I think this is because she was nice to me while pregnant. Idk... who even knows. But the other day I could hear them arguing and fighting outside. Later on we go out there and there is coffee spilled all over the windshield. You can tell it was purposefully splashed on it and I saw an empty coffee cup in her back seat. What should I do?

My fiancé also smokes cigarettes on the back porch (THEY SMOKE TOO) yet every time he does they come out there and give him dirty looks. Even asked him to smoke somewhere else. When THEY SMOKE back there too. We aren't even close to their apartment so I just don't get it. Smoking is gross and I don't blame them.......IF they were non-smokers themselves