First you may wish to take legal action against the property manager and/or landlord:1) The landlord has an obligation to prevent other tenants from disturbing your right to peaceful enjoyment, in addition to landlord's own obligation to not disturb you. You could look to bring a legal action against your landlord, to force them to take action against this tenant.2) In the process of doing the above, you will be able to use the legal tools of "discovery" to get that tenant's name, etc.--that is, if the landlord does not, at the time, voluntarily give it to you to cooperate.Note that you might not be able to sue for nuisance in small claims; small claims courts are very limited in what they can or will hear.