Sales property illeagal in hyderabad.

Dear Sir, I thought of seeking your advice on the problem my family is facing. My father owns a plot(non-agricultural) in Hyderabad- (kimtee colony , Tarnaka, Secunderabad, which was purchased by my father (in 1985)when he was alive. Original documents are in my Mamaji possession. There was a compound wall & shed constructed in this plot. We were planning to visit that place and think about built it. In the meantime, we came to know that someone is cleaning the place. We approached registration office(in Dec 2010) for EC and realized that property was sold by some person claiming as my father`s fraud G.P.A.. A] Photograph of my father affixed on the photo form is not a photograph taken for the purpose of registration, but is a cut-out photograph, having been cut from a group photo, wherein late my father is seen looking at somebody else on his right side profile. [B] The thumb impression appearing in the document is not that of late my father. [C] No identity proof of late my father was produced at the time of registration which is mandatory. [D] Out of the alleged consideration mentioned in the document as Rs 37,68,000/-, major part of consideration in a sum of Rs 34,18,000/- is shown to have been paid in cash and the balance amount of Rs 3,50,000/- by way of cheque No.503915 dt.18.3.2008 drawn on Syndicate Bank, Kukatpally branch shown to have been issued in the name of my father . Why they issue such amount in the name of my father, When as per G.PA. Mr. seller hold the plot. [E] As Syndicate Bank, Kukatpally branch confirm that purchase party. Not having any saving or current account in the branch they issue bank certificate,) It means she is not issued any cheque of Rs. 3,50,000/-. 1) Is it within the registrar's authority to cancel the illegal sale deed? Few lawyers, whom we approached, said 'yes' and few say it has to go thru civil case. Regards ANAND KIMTEE