I had this same problem! My neighbors let their German shepard and lab mix run free. Id gone as far as calling the police when I caught them peeing on my bushes a little after midnight. Well, I would have filed a report against them, but they couldn't do it annonymously, and I didn't want to be "that neighbor."
Sooo I went to my county's website, printed off the Animal Control laws, highlighted the rules about dogs being off leashes, etc. I also highlighted fines for breaking these rules. Stuck the papers in their paperbox and magic! No more dogs running loose, and it's been almost two months! And they have NO idea it was me
Not sure if it will work for you living in an apartment tho. But try to find out what your county considers a "nuisance dog." Good luck!