Legal heir

My uncle committed suicide on 30th Nov 2018. He had made a will somewhere in 2011 to 2013 in which he had made me legal heir of his room that he owned in a Chawl. It was registered in bandra kurla complex. I don't have the original will as it has misplaced by my uncle. I along with 2 witnesses had gone with my uncle to register the will and got it registered. He had won a case many years ago regarding his room in the Chawl that he has been staying for over 35 years. Now the owner of the Chawl who lost the case in lower court is trying to take over the room stating my uncle had no children and he is owner of the chawl. He may not be aware of the will which my uncle made. The keys of the house are with the police who are investigating suicide case. How can I get copy of the will which was registered in bkc and stop that person from selling the place to someone else. I intend to donate that place to religious chapel where prayers will be conducted in my late uncles name. I have contacted the person who got the will registered but he is saying it will take sometime to find out about copy of the will as I don't know the exact date when the will was registered. I never xeroxed the will. Please help me I don't want these strangers to eat my uncles room. I want to give it to church instead where they will pray for him. Please help me.