KATHUA: A video of BJP leader Lal Singh 's brother using "derogatory" language against J&K Chief Minister Mehbooba Mufti during a rally here has gone viral, with NC leader Omar Abdullah demanding that an FIR be registered against the person.Senior BJP leader and former state minister Lal Singh earlier today led a massive rally from Lakhanpur to Hiranagar in Kathua district to press for a CBI probe into the rape and murder of an 8-year-old girl in January.The 26-second video clip purportedly shot during the 'Dogri Swabhiman' rally shows Choudhary Rajinder Singh , younger brother of Lal Singh, atop a vehicle and using abusive language against the chief minister.A group of people on foot can be seen enjoying and clapping in the video as the rally moves.Former chief minister and opposition National Conference working president Omar Abdullah reacted sharply to the footage and demanded registration of FIR against the BJP leader's brother."This is absolutely unacceptable language used against @MehboobaMufti & is unequivocally condemned with the request that @JmuKmrPolice file a FIR against this abusive individual," he wrote on Twitter.