A suspected Muslim insurgent shot to death a primary school teacher Monday in a classroom full of children in violence-plagued southern Thailand, police said. The gunman disguised himself in a student uniform, entered the fourth grade classroom and killed Prasarn Martchu, a 46-year-old Buddhist teacher, while he was teaching at a public school in Narathiwat's Rue So district, said police Col. Banlue Chawej. "The teacher was still holding a piece of chalk'' when he was killed, Banlue said. The gunman fled on a motorcycle with a getaway driver. The primary school, which has 11 teachers and about 250 students, was temporarily closed after the shooting, police said. Prasarn had worked at the school for more than 20 years. Prasarn is the 44th teacher to have been killed by suspected Muslim militants since 2004, said Sanguan Jintarat, head of the Narathiwat Teachers' Association.