The 18-year-old fired at the monkey, which had attacked and injured people in Bachrauli village, from his air gun leading to its death, official sources said.
Taking the langur to be a form of a deity, members of the other community from about ten villages gathered in Bachrauli, the sources said.
SDM Sanjay Khatri and Circle Officer Sukhsagar Shukla reached the spot and pacified the agitated villagers by assuring them action against the youth and sending the body of the animal for post-mortem examination.
Security personnel from Kunda, Manikpur, Sangramgarh, Nawabganj besides Hatigava police station, under whose jurisdiction the village falls, were rushed to the area to maintain order.
Police and the PAC have been deployed in strength to prevent any untoward incident, the sources added.