If blasting, you may be able to zero in on the flat. What's the music - Indian or Chinese or Malay or other language? The police may not be enthusiastic to help you solve this. They prefer to score points for promotion by cracking drug busts or sensational murders. You may have to tell them that you may complain to the MP or Police Commisioner if they don't act on it.
I don't think it's so much of a scoring points for promotion thingy like you said but more of, there's nothing much they can do except issue warnings. What else you expect? Press charges against the people causing the noise and waste taxpayers' money bringing them to court? That's why for one-off situations they are usually less "enthu" about it but it'll be a different case if the noise pollution is persistent...
Anyways TS hasn't replied in two days so I suppose maybe it's just a one-off case.