From the Catholic reaction of priests in Pakistan it would seem that the 17 year-old victim was Catholic. He was the only Christian in the school, having just enrolled three days before. He was actually killed in August 2016, but the account in AsiaNews is current. According to some testimonies he was killed for refusing to become a Moslem. Truly, he died a martyr. See this account here.
AsiaNews, Kamran Chaudhry: “He was my eldest son. We thought the city school, 6 kilometres away from our village, would help him further his studies. I took a loan and we went together to buy his new uniform. He wore it only for one day and it became his shroud,” said Elyab Masih, father of Sharoon Masih, the Christian student killed by classmates in Burewala, Punjab, who spoke to AsiaNews about his son killed in an act of religious racism. “I could not even have a close look at his body,” he lamented. More here.