Promoter is unlawfully keeping the original deed and other relevant papers of the Landowner

When a landowner gives his land to the promoter for building a multi-storeyed building then they have to enter into an agreement and the future course of actions are based on that agreement. I hope you have already done that long back before giving the possession and building rights to the promoter. The agreement contains everything from the size of the land to the consideration of money and number of flats the promoter will be giving to the landowner as a full right on those properties. You must be keeping the agreement with you. That will be required when you approach a court of law for relief to you in these conditions. Once you get the consideration money as per the agreement and also get possession of the agreed number of flats then the flats are to be registered in your name in the registrar office or wherever as per the state Govt procedure. You are probably referring those registrations as the deeds. You are supposed to keep the original of these registrations of the flats with you as that is required during the sale of the flats where you can mention and attach a copy of same in the sale deed. As per your narration the promoter is keeping these important property holding documents with him and police is also not helping you in the matter.

The only recourse now is a legal action and to begin with take the help of a good lawyer who is well aware of property cases and ask him to prepare a legal notice to be sent to the promoter by registered acknowledgement post asking him to give all the documents immediately back to the you. Please mention the terms of the agreement also where he is bound to follow it in a proper manner. In the end you have to mention that if the documents are not received within say 10 days time then you will be forced to go to the court of law and submit a case against him and the expenses of the case will also be liable on him in due course. I hope with this notice he will surrender the relevant documents. If he does not then lodge a case in court. Courts take time but you will get things sorted out by the courts.

When the land is given for development, you should have made a legally valid document. In that document, the details regarding the land ownership, number of flats to be constructed, the share of the developer and share of the landlord will be clearly mentioned. That document also should be registered. Was it done? If, do you have a copy of the same? Now the questions whether the three flats are registered on your name or not? If you got it registered you can take a certified copy of the registration documents of all the three flats.
With these documents you please approach a good lawyer and send a lawyer notice to the promoter telling him to hand over the documents within a specified time. If he is not responding you have to file a case. In these land issues, police will not interfere. So you have to depend on the court only.