The police said identity documents including Aadhaar numbers have also been seized from them.
The three Pakistani nationals have been identified by the police as Sameera, Kashif Shamshudin and Kiran Gulam Ali, the Indian citizen is Mohammed Shihab, a native of Kerala.
The police raided their apartment on a tip-off about Pakistani nationals staying illegally in the apartment block. But the two couples are insisting that they ended up breaking the law because they were in love.
The four had first met in Qatar. It is there that Mohd Shihab fell in love with Pakistan girl Sameera. But since their families objected to the match, the couple came to Bengaluru. Also accompanying them was another couple, both Pakistanis, whose families too opposed their love marriage.
The four decided to come to India; the three Pakistanis first reached Nepal and then crossed into India last year, according to their initial interrogation by the police. Bengaluru police said they were yet to verify the version given by the Pakistani nationals.
Over the next few months, they also managed to get official identity documents including the Aadhaar number and a passport.
"We have arrested these four persons under various section of Passport Act, conspiracy and creation of false document, misrepresentation etc. Interrogation is going on not only by state police but also by central agencies to verify all the information given by them," said Praveen Sood, Bengaluru Police Commissioner.