The Extradition Act,1962
21. Accused or convicted person surrendered or returned by foreign State or commonwealth country not to be tried for previous offence.
Whenever any person accused or convicted of an offence, which, if committed in India would be an extradition offence, is surrendered or returned by a foreign State or commonwealth country, that person shall not, until he has been restored or has had an opportunity of returning to that State or country, be tried in India for an offence committed prior to the surrender or return, other than the extradition offence proved by the facts on which the surrender or return is based.