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I'm Lucy, and I'd be happy to answer your questions today.
There is no specific law that gives tenants a right to information regarding other tenants in the building. There is also no law that would prevent you from knocking on the door and introducing yourself in an effort to learn their names. You also have the ability to call the police if there is suspicious activity occurring. If police file a report, they'll give you a copy. It's possible someone would also come out and talk to them about the noise if they're not doing anything.
When a person has a pending lawsuit, it IS possible to subpoena information needed to prove your case, and that includes lease information or other documents that would help you identify the people living above you. To do that, you would either need to hire a local attorney or file a lawsuit against your neighbors for creating a private nuisance. Alternatively, a private investigator may be able to help you get the information you're looking for.
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