El-Arish - Suspected Islamic militants gunned down a Coptic Christian teacher on his way to school in northern Sinai on Thursday, the second killing of a Christian in less than a week in the turbulent region, officials said.The 50-year-old Gamal Tawfiq was shot in the head by two militants on a motorbike who were following him as he walked from home to work at El-Samran School in the morning in the city of el-Arish. A security official said the Islamic State's affiliate in Sinai is suspected in the killing.A school official confirmed Tawfiq's death to The Associated Press but declined to give details. Both officials spoke on condition of anonymity because they were not authorized to speak to reporters.Also in el-Arish, suspected militants gunned down a local vet, Bahgat Zakher, on Sunday and in late January, Wael Milad, a merchant was killed by militants who stormed his shop. Both were Coptic Christians.The Islamic State offshoot in Sinai — formerly known as Ansar Beit al-Maqdis — has been the most active militant group in the region and has claimed responsibility for most of the attacks that have targeted the police and army forces.Several Christians were also killed in Sinai last year, including priest Rafael Moussa and health ministry employee Massak Nasrallah whom the militants stopped on his way to el-Arish and asked him about his religion. When they learned that he was Christian, they opened fire and killed him, reported the Coptic Watani daily.Egypt is home to one of the world's oldest Christian communities, with Coptic Christians accounting for roughly 10 percent of its 92 million people. The Copts have long complained of discrimination and have been top targets of Islamic militants. Attacks against them increased after the military's ouster of the country's Islamist president, Mohammed Morsi, in 2013. Christians, along with a large sector of anti-Islamist Egyptians, have supported the army.