For the details of the transaction you need to contact the local Sub- Registrar office and take EC (Encumburance Certificate) for the particular property in which you will get all the details like who was the seller and purchaser and the year of transaction in which it is sold.

The EC will reflect a document number by taking a certified copy of which you will get all the details like the residential address of those people who made the transaction and can further deal with them fro getting the property back. Before this you are suggested to take all the proofs that you have in respect of that property.