Legal heirship certificate not available

If possible try to get the Certified Copies from the respected Sub Registrar Office for all the document (including 1974 & 1980 documents). Where as you can apply for an EC from 1970 or prior to that of the scheduled property from SRO. There you can find the chain of the property owners.

I have copy of all the documents including the 1974 and 1980 documents. Only thing that i dont have is the legal heirship certificate for the heirs of the first owner. I also got the EC from 1979 which shows the legal heirs (not all their names though. it shows the wife's name and their no. of children which matches with the no of heirs listed in the sale deed & Power document and also it shows the name of the power agent mentioned as power agent). I also have checked the chain of original sale deeds executed so far as well as the power documents and patta.

Do we need to check any additional documents and can someone claim as legal heir to the property after all these years?

Have you read the conditions in GPOA which is executed in 1974 ! There will be sum conditions in that regarding the sale transactions, if the POA holder is having the rite to sell the property as per the GPOA document - then there is no issues to purchase this. Anyway which way you already got checked all the original documents including Patta and other. Only thing in this is find the original property owner and is the legal heirs of the property is correct or not as per documents. Thank you