"We have arrested 13 persons...Some of them are members of Bajrang Dal," said S Murgan, the Mangalore police commissioner.
The 29-year-old man was in his car with the woman on Monday evening when he was surrounded and attacked by the mob.
The attackers thrashed the man, stripped him and paraded him through the crowded market area before tying him to an electricity pole. The images were circulated on WhatsApp. The beating continued for nearly an hour. The police arrived when the visuals were flashed on local cable channels.
The man and the woman both work at a mall.
The man told the police that he was attacked when he was on his way to an ATM to withdraw money for the woman, who had asked for a loan.
The mob allegedly also humiliated the young woman when she tried to stop the assault.
The Bajrang Dal is a rightwing Hindu outfit affiliated to the Rashtriya Swayamsevak Sangh, the ideological mentor of the ruling BJP.
Mangalore, a city familiar with religious polarization, has seen many moral policing incidents in the past. In 2009, activists of the notorious Sri Ram Sene group stormed a pub, dragged women by their hair and slapped them, accusing them of denigrating their culture.
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