Harassing neighbour

Hello sir, My parents live one of Jharkhand city. They possess a property on which they are living and also getting some rent for livelihood from that property. Property is constructed in two phase. 1st part which is made 33yrs ago, now is in very weak condition and can collapse any time. And vacated too. When the building was constructed, relationship with neighbour was good and the first floor was built together. Now they have added support and renovated their part. And my parents want to demolish the building to build a new one. For this they want to cut the part in between first so that neighbour's building doesn't get damage. But they are intended to buy the property at lowest cost or no cost. For this they have started harassing my parents. Whenever my parents try to cut the dhalai safely, they creat nuisance and call the police and stop the process. When my father went to police station to lodge the complaint they dont entertain.They too support them as they get money as bribe. Now they are helpless. Everytime police comes and stop the working and asssures that they will get the solution. Now please suggest what to do.