I think Massisa's hubby was the mastermind behind the attack in pushkar which killed sandhya? After that he went in hiding . His motive behind killing might be he hated women working, people using modern technology which was common in season 1( meena, sandy and emily worked). Massisa worshipped her husband so she hated women like Sandy. Uma's brother hated masi's hubby and had evidence which he threatend to give to police which shows his involvement in the attack. So Masi made Uma like her hubby and wants evidence that will prove her hubby innocent.