Land grab in Madurai

My dad bought land in Madurai in 1982. It was sold last June by some stranger. It is empty undeveloped 1 ground land worth about 70 lakhs today. So this is what happened, some 84 year old man claimed that he owned the land, lost the registration documents and filed police complaint. Police declared the loss and they got all the information from Registrars office to enable resale. This 84 year old man sold to 3 others within 2 weeks of filing police complaint. After that speedy sale, the 3 people sold the land to a local council member, basically a politician in power. This person is a popular local guy and is also in the real estate construction business. It is just like the movies. Except it is our life now. Talking to lawyers. What is our recourse. It is clear the registrars office, the police, the council member all colluded to grab this land. They basically got it for free. Please help if you have any suggestions. Also if you have any land property please secure it, there are vultures everywhere trying to take it for free.