Capital Gains arising from Property transaction through POA

I bought a property (property 1) from a middle person who held Power of Attorney for that property and got the sale deed registered on 20/6/2011 for amount 17,04,000, But came to know immediately after a day or two that the property had double document issues(having another track of duplicate ownership by another person illegaly) hence confronted the middle person and he agreed to replace it with another property(property 2) he had in same locality. Within two months we got that property 2 registered with sale deed in my name but he(middle person) was not willing/ready to register the property 1 in his name(as he said multiple registrations in short span will create problem for him to sell it out later) and hence he got a Power of Attorney from me and separately on a stamppaper he mentioned that he had paid/compensated me for the property 1 and took the same from me. The guideline value for the properties were same (and minimal) during these transactions. But now he has sold the property 1 on 5/10/2015 which I got to know a week before through the Encumberance certificate which shows 72Lakhs as guideline value registered and the actual cost of sale/transaction as 56,40,000. I am worried as he took only the Power of Attorney then and the property transfer now shows from my name and hence the LTCG that would arise out of it will be showup in my name for IT dept. I spoke to him regarding the same but he easily and negligently says you take care of the taxes. I have all other documents but the Power of Attorney he took from me and the document written in stamp paper on that day of exchanging the property is not with me but i believe i can get the copy of POA (alone) from SRO. Please help me with suggestion/directions on the way to handle in the current scenario, also as this year IT filing dates is nearing closure is there a way i can intimate my stance to IT dept in a formal/procedural way and should I declare it in my IT filing or any Legal notice/filing case and keeping that copy intimated to IT dept will be required, please help with suggestions.