They said he had been sent to Dubai last year, provided with a Pakistani passport and told to set up covert networks in India.
Pakistani passports are issued to the citizens of Pakistan for the purpose of international travel.
Both father and son had beaten the immigration system using Pakistani passports.
He was traveling on a Pakistani passport, Indian officials said.
Pakistani passports had been in the possession of the arrested.
But airline workers opened his bag and found at least 38 Pakistani passports, she said in a speech.
They said two guns, computers and a satellite phone were seized from the suspects, one of whom was carrying a Pakistani passport.
For a little more, a Pakistani passport can be obtained, too, Quetta residents say.
For example, Pakistan requires applicants to be interviewed before a Pakistani passport will be granted.
Initially on Pakistani passports there was a printed list of countries which could be visited.