Property document

Hi, We have found one property in Bangalore. This property belongs to a person called Shivanna. Shivanna has got the property registered by the previous owner called Narasiah in 2006. Naraisah has got the property from the previous owner registered in year 1995. In the year 2005, Narasiah has entered into an agreement with the bulider that he would register the property to the buillder or any other person pointed by the buider. Shivanna has paid the builder to get the property. The bulider had acquired hectares of land from Narasiah and formed a layout, created sites and sold the plots to several people. SHivanna does not have the sale deed for how narasiah acquired the property. There are several people in the layout who have got the plots registered by narasiah from the builder. So its not possible for all plot owners to have original sale deed of naraisah. Is it OK if we have a certified copy of Narasiahs deed and then get the property registered in our name by Shivanna. Checked the latest encumbrance certificate and it is in the name of Shivanna. Is it safe to go ahead buying this?