Transfer of ownership from BDA

I have purchased a house from a person who got the plot from BDA in 1977 under lease cum sale agreement from BDA. He constructed a house on this plot in 1980. I purchased this house from the owner in 1982 with an agreement to transfer the house to my name after the lease period which would then end in 1987. He has given me a power of attorney to deal with the property and transferring all his rights on this property to me.Also he has handed over to me all the original documents pertaining to the property such as allotment letter approved building plan from the municipality etc.I could not meet the owner even once as i was abroad till 2015 when I returned to India permanently. In the year 2006 I asked my wife to make an application to BDA to get the property transferred to her name.But BDA said you have to bring the original owner to BDA office to verify the power of attorney for the transfer the property to us. Then we started to find out the owners where about since 2006.However the owner was not in Bangalore and the temporary address of owners brother who was the point of contact for all transactions was changed and he was also not traceable. till today all our efforts to find the original owner have not been successful and we do not know whether he is even alive or dead. we are in the physical possession of the property since 1982 to till date continuously and continuously paying the the property tax till to date but in original owners name. 13 years have passed since BDA asked us to bring the original owner to their office through a written NOTICE.We are struck now as we could not trace the owner so far. What is the solution now to get the property transferred to us? Please advise whether we can claim this property on the basis of adverse possession or any other legal ways. satish Deshpande