The killing in broad-daylight of Kamlesh Tiwari has caused massive outrage across the state and on social media.
He was killed in Lucknow, the state capital of Uttar Pradesh.
Angered by the killing, Hindus are demanding the immediate arrest of the suspected killers captured on CCTV before fleeing the murder scene in Lucknow.
Tiwari has been facing threats on his life since 2015 over his allegedly inflammatory remarks about Muslims and the Prophet Mohammed.
There is deep resentment among people in the Hindu community, some of them even making calls on social media for citizens not to rely on the local administration ahead of the most important Hindu festival of lights, Diwali.
People have been reminding the government of the threat to Kamlesh Tiwari since 2015 when more than 100,000 Muslims gathered in Muzaffarnagar- a Muslims dominated town, 83 miles from Delhi to protest against him.
After the protest march, a Muslim cleric announced an Rs.51,00,000 ( approx..$72,000) reward for Tiwari's head. People are now demanding that the state government led by Hindu leader Yogi Adityanath arrest the cleric.
As per the CCTV video of the murder, the killers visited Tiwari’s office in Lucknow in saffron-colored clothing on the pretext of handing over a box of sweets. Soon after walking in, the assailants opened the box, took out a firearm, sprayed Tiwari with bullets and fled.