Pleading Fraud Plot Case with NAB

I happened to buy a plot from a fraud housing society almost 20 years ago. There are many other victims of the housing society. Some victims and myself put up a complaint with NAB a few months ago. NAB has determined it to be a case of cheating public at large.

Now NAB has asked me to appear before an investigating officer and present the original allotment letter with the receipts of the payments I have made. The vicitims who have already appeared before NAB informed me that NAB will keep all the original documents and then give me a receipt. If the original documents are not handed over, then NAB does not consider the case any further.

I would seek some advice from the experts here.

(1) Why does NAB keep the original documents?
(2) What if I just present the notarized copies of the documents?
(3) What action is NAB going to take if it has judged it to be a case of cheating public at large? Will it help me get back only the original sum of money or is there a possibility of getting a plot of land as the fraud society does have possession of some land which is still undeveloped. What is the likely action?
(4) Any advice that I should follow when appearing before the NAB investigating officer.

Thanks for your help in advance.

A.

is this fraud involve some govt. official / govt society etc if not than according to a new law NAB is not authorized to pursuit the cases of private societies or person. Also there are thousands of real estate cases pending in NAB from decades and still no result. Look at the cases of J&K or ministry of commerce etc. so its better to save your energy, time and efforts.

I would suggest appearing before NAB since appering would mean there are chances of getting something than not getting at all by not appearing. secondly, the NAB does have the jurisdiction over some cases related to property when they determine it exceeds a certain limit of money.
As far as the papers and original documents are concerned, I would suggest consulting a legal advisor to get a better picture. nontheless, make a copy of your documents in good resolution, scan them before submitting them, and also notarize them so in case NAB, which is known for callousness, misplaces them or is not able to return them, you have something to stick to.
and last but not the least BEST OF LUCK, that like getting a bite from lion mouth.

Thank you for your valuable input and advice.