Bandhe haath (1973)

Shyamu is an orphan, living with his mentor, and has lived a life of crime. While his partner is recuperating in hospital from a injury incurred on the job, Shyamu decides to go straight. In a case of mistaken identity, he ends up in showbiz and gets a gig as a playwright for a beautiful starlet when he shows up instead of popular writer Deepak, whom he looks just like, and is met with considerable respect. One day Shyamu goes to Deepak's house for something and discovers just how identical they are. Unfortunately, Deepak is on his death bed and Shyamu, reverting to his evil nature, "helps" Deepak along on the way to his demise and takes on his identity, even down to learning to copy his handwriting. But not everyone believes the goings on are all above board, especially Deepak's girlfriend and a certain police inspector.