Property wrongfully occupied by relatives, govt scheme construction

My grandfather handover the property to my relations for maintain property and grand father migrate to another district.After long years my father return to previous village and ask my relations to return property,but they are refused and construct the house already and construct toilet under govt sponsored scheme.but the property remained with our grand father name only till date.my relations telling my grandfather receive some amount from relatives.but they didn't have any proof.so please guide me how I will recover that property from my relatives.govt also without verification they construct the toilet in my grand father property,any legal action against govt required to get relief?religion Hindu only