Don’t purchase the property . Original chain of documents is necessary 

2) POA executed by seller in favour of his family member is required to confer clear and marketable title to property 

Don't buy.

See if there is registered deed available and in deed it is mentioned that seller purchased through POA and name and details of POA is mentioned in deed then there won't be any problem taken an indemnity bond and Affidavit of lost POA from seller.

the copy of the POA must be attached to the sale deed between builder and seller

the POA original should remain with the grantee only

so if its lost, then it will not in anyway affect the transaction between your seller and you

you can proceed with the deal

your seller can simply cancel and revoke that POA by writing a letter to his family member to whom it was granted 

1. As per the information mentioned in the present query, makes it clear that the seller bought the property by issuing a POA at that time in the favour of a relative, and now the same POA is missing.
2. Apart from the POA, seller should have additional documents also like registry, mutation etc. on his name.
3. If he doesn’t have such documents then he can get the certified copy of the same from the same, if it was given there.
4. Otherwise, please ask him to provide any other documents whcih can show that he has right over the property.
5. And generally, POA is just the authority to a person to execute some transaction relating to the property on the behalf of the real interested party, but not the final document to show the ownership.

1) You can make tripartite agreement of sale deed and get this sale deed registered in sub-registrar office.

You can pull a second copy/certified copy of this POA from the registry office. There upon, after doing a due diligence, you may go ahead to make this purchase. No problem. 

Dear Client,

Purchase of property is clear but chain of document is missing, without it, further sale or loan may not be possible.

Dear Sir 

It is risky to purchase it but if the previous owner ready to come over and sign as CONSENTING WITNESS it is 100 % strong. if original owner send NOC it is 80% strong 

If the POA is registered then you can easily obtain a certified copy of the same from the sub registrar office. If it’s not registered then file an FIR to that effect and give a public notification in the local newspaper. After the publication, execute a new POA.

The transfer of immovable property by an Unregistered POA is not valid in law.

Now the POA itself is missing.

This indicates something major is missing in this deal.

The seller seems to be in abroad, hence there can be no convincing answer given by the representatives of the title owner to sell this property. The title holder, since residing in abroad will not come to India to clear the litigation in the future, if anything arises.

It would be better you obtain a proper legal opinion from a local lawyer before buying this property.

1. IF the earlier Sale-Deed was properly Stamp Duty paid and Duly Registered before the local office of the Registrar of sub-assurances, by annexing the POA document, THEN today there is no legal necessity of such POA, for future transactions, provided the present sale-deed is also duly registered.

The PoA has to be duly registered. If it was not done, do not evince any interest.