Fraud , cheating

My brother in law and his family duped me for 90 lakh cash amount given by me since 2009 till now as a safe deposit to them , to purchase myself a good flat when required. Also in september month they duped me for 2.5 kg of fake gold.As they being a gold merchant i had kept this gold with them since 1 yr..and had took 55 lakhs against that gold. In september month they told that gold rates are falling sharply so you give us the money and take back your gold.They continuously pressurized me to do that transaction ,so on 18 sept I paid them the 55 lakh cash but in return they gave me fake bars.he had kept his cctv off ,also he was very nervous and shivering.he weighted the fake gold bars made a rough chit of that bars and handed it to me.he then told that i have to urgently go to the bank , so we both left the office in hurry. i was also short of cash ,so i wanted to keep this gold bars somewhere else and again get cash against it. in 15 min i reached a reputed showroom to keep the gold bars..and there he told me that all this are fake bars.i was shocked and panic-ed , i continuously tried calling my brother in law from there,but he didnt picked up my phone, then i called n met my father in law , but he reacted in a very abnormal way.after that till now, i involved my family, his and my relatives to solve this matter but this was all in vain. Infact when asked for my money - 90 lakhs cash and gold,they started telling that forget everything, or do what you want to do, also if u go to the police we will manage them,as it is we have to spend your money only. i m in a serious trouble now..i have all my savings as well as the gold . i m completely ruined and bankrupt now, i dont wont to spare them now, i want to go legal as well as to police now. please help me in all legal ways how i can punish them recover my savings and gold from them. The things that i have - 1) The chits of their hand for 90lakhs cash given to them with signature.15 lakh in white. 2) The chit having fake gold bar weight given to me with fake september. 3) I can show this cash in hand in A/c books. 4)also i can show this 2.5 kg of gold in a/c but in the form of ornaments. please help me , so that i can see this cheaters behind bars.