Gambler (1971)

Raja (Dev Anand) has been abandoned by his biological mother at a very young age, and grows up with Master (Jeevan), a criminal don and card-sharp, who would like Raja to continue working with him on a commission basis. Raja learns all that could be learned about playing cards, quits work with Master, and starts work on his own. He succeeds considerably, and soon gets rich and wealthy. He falls in love with beautiful Chandra Gangaram (Zaheeda), and would like to marry her. But her father would like her to marry U.K. settled Ram Mehta(Sudhir), before Raja could do or say anything against this alliance, he is charged with the cold-blooded murder of Master. The climax in Raja's life is in the Court Room where he will find out about his past, and about his parents - while he awaits the outcome of the trial. From http://en.wikipedia.org/wiki/Gambler_(film)

Mystery, Thriller