Fake registry of land

Sir, One of my neighbour have illegally acquired a land of about 5000 sq feet. It was a vacant block few years ago and now they have built a house over there. In the colony some says the owner of the land was gone abroad years ago and few people around says the land was suppose to be public park. Someone complaint about them in local police station but nothing happened as the fake owner showed the fake registry documents to police which everyone knows in the area that the documents made are not real. The bribe the authorities who have right to make the registries etc. They also bought a fake previous owner of the land and made a plan by saying that they the land was sold to them. Now they got registry documents on their name. Everyone knows it's fake but no one knows how to prove them wrong. Instead of public park there is a unwanted house built up. What's the procedure to prove them fake and to whom we can approach to lodge complaint against them all. As to make fake documents there must be lot of govt employees will be involved. How to break the chain? Is it really a crime or is it acceptable in India now? Advice needed urgently so that these kind of crimes bring to an end someday. Thanks in Advance. Land is in state Punjab city Patiala. Many thanks in advance.