conviction in foreign country

FOR WHAT CRIME OR WRONG HE IS CONVICTED OUT SIDE INDIA AND YES HE IS LIABLE FOR THAT ACT IN INDIA

when any body is convicted in foreign countries,he is already time served in prison for that crime.then why he is liable in india fo the same crime?is it double jeopardy?i think you have to check your answer.one crime cannot be convicted twice whether in india or foreign.it is against natural justice.

thanks