Sambhal Violence: What led to violent clashes?

Two pictures of Sambhal violence have been released in which rioters are seen tying cloth on their mouths. In Sambhal, the administration has released a video of the court commissioner and lawyer Vishnushankar Jain going for the survey of Jama Masjid...the Muslim side had alleged that the court commissioner and Vishnushankar Jain had reached for the survey with a procession chanting Jai Shri Ram. But the truth of the allegations was revealed in the video