Yakeen
Rajesh Sharma, working with the Indian Government on a top secret research project, has to deal with enemy agents, explosions, murder and last but not least a dangerous look-alike.
Starring Dharmendra, Sharmila Tagore, David Abraham Cheulkar, Kamini Kaushal, Anwar Hussain, Asit Sen, Brahm Bhardwaj, Helen, Mukri
Watch "Yakeen" on Amazon released in 1969. It's a mystery and thriller movie, and has a rating of 6.8 out of 10 from Imdb which is usually fine for this kind of movie, and is currently only available for purchase or rent.