Recovery of amount given to friend

I gave INR 50,000/- to one of my friends about 4 & 1/2 years back. While taking this loan he promised to return back entire amount within 3-4 months. After chasing for almost a year or so for returning the amount, I learnt from that friend that he actually gave that amount to his younger brother (without my consent or even any info to me) and now i need to chase with his brother for recovering the amount. His brother, who was unable to return the amount agreed for paying 2% monthly interest on the amount. Till Dec 2013, he paid interest regularly. However, since Jan 14 he neither paying interest nor refunding principal amount. After chasing very hard, in Jan 15, he (my friend's brother) handed over 3 undated cheques - one for INR 50,000/- towards principal, and 2 cheques for INR 10,000/- each towards balance interest. He told me that within a month or two he will arrange for funds and take back those cheques. It's now 4 months am still waiting for recovering the amounts. My queries are:- 1) should i deposit the principal amount cheque and once bounced, file an FIR? 2) should i send the notice through a lawyer before depositing a cheque? 3) can i register FIR complaint against both - my friend and his brother? Thanks in advance for your efforts in this regard. Thanks & Regards, Ashish Agl