India has long struggled with religious violence, but in recent months the problem has taken a gruesome new form. Across the country, gangs of Hindu men have lynched Muslims who they accuse of killing cows or eating beef. Known as cow vigilantes, in some instances mobs have killed or injured more than 150 people since 2015. India's Prime Minister, Narendra Modi, has made a plea for calm, but 2017 is set to be the worst year for attacks to date. Reporter Mirren Gidda meets a group of vigilantes, unconnected to any killings, who take her on one of their nightly hunts for people who may be harming cows. She also meets Muslim families who've lost loved ones to the mobs, among them a mother whose 16-year-old son was stabbed to death. Her report is an emotional account of the tensions and violence spreading across India, and provides a detailed look at why the vigilantes do what they do.