A First Information Report or FIR was filed after a video showing Rajinder Singh using abusive language against Ms Mufti during the rally organised by his brother Lal Singh on Sunday went viral.
Lal Singh was forced to resign as minister a month ago for participating in a rally that defended the rape-and-murder suspects in the area. Since then, he has been holding protests in Jammu and Kathua.
On Sunday, Mr Singh organised a "Dogra Swabhiman" rally attended by thousands of people at Hiranagar in Kathua. Mr Singh lashed out at the police department's Crime Branch probe which has led to the arrest of eight accused including four policemen for rape, murder and destruction of evidence.
He said the Crime Branch probe and media coverage of the incident has stained the image of Dogras of Jammu and demanded a CBI inquiry.
Mehbooba Mufti tweeted:
Former Chief Minister Omar Abdullah strongly condemned the invective against Ms Mufti and demanded action against him.
I want to thank everyone from across the spectrum for their support & solidarity today. The abusive statement & its diction, reflect the horrid mentality behind the Kathua rape case. https://t.co/zBN1FwXgAh- Mehbooba Mufti (@MehboobaMufti) May 21, 2018
"This is absolutely unacceptable language used against @MehboobaMufti & is unequivocally condemned with the request that @JmuKmrPolice file a FIR against this abusive individual" Mr Omar tweeted.
The police said they have filed an FIR at the Kathua police station and action will be taken against the BJP legislator's brother.
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