cash fraud with some persons

Asslam-u-Alaikum
I want to ask, my younger brother has made some cash fraud with some persons & signed a stamp paper by involving me and my father. In stamp paper, he wrote that all fraudulent money had given to his father and elder brother started a business. He stole one check from my chequebook and copies my ID card and father too. Attached my check and ID’s copy with that stamp paper. How can I protect my father and myself in this scenario?