Land Encroachment

Dear Sir, My name is Jerry Joseph, working at one of the steel Industries in Riyadh, Saudi Arabia. I am basically from Bangalore. In the year 2009, i purchased a plot of size 30x47 feet in Bangalore North and also registered the sale deed. Every year i go on vacation and i used to check my plot to be safe. Last December i wanted to start construction of my house but to my astonishment i saw a building with a Ground and First floor already constructed by a retd. police inspector. I discussed with him about my property. He showed his papers that he had purchased the plot from the Sister of the person who sold the same to me and registered the sale deed during 2010. Thereafter i took up the matter with the person from whom i bought the plot. He says that his sister has sold also the other two plots which is belonging to him which is adjacent to my plot. Therefore he has filed a case against her. He is now asking me to wait for the demolition order of the building. I am very much worried since i paid a lot of my hard earned money sacrificing my family life. Now after years of working hard i am not even able to have my own house. Please advise me what should be done in this case to regain my property.