A student suspected of joining in an armed raid that killed six at a school in Kenya's far north Saturday was stoned to death by angry locals and his body burned, officials said.The suspect -- a suspended student at the school in Lokichogio -- was arrested before irate locals forced their way into the police station and dragged him from his cell.He was being held over the school attack that left five students and a security guard at the boarding school dead."Six people were killed in the attack, including students, and we have others injured," said Seif Matata, Turkana county's commissioner.Matata said the incident occurred at around 3am while students at Lokichogio Mixed Secondary School were asleep in their dormitories.Turkana governor Josphat Nanok said 18 people suffered bullet wounds in the attack.Members of the Toposa tribal militia from South Sudan, 200 kilometres (124 miles) to the north, are believed to be responsible for the violence.Matata alleged that a suspended student, identified by officials as 20-year-old Abraham Lochor from South Sudan, led the raid."The suspect was held at Kakuma police station for interrogation over the morning killings, we are trying to establish how they managed to get him. It's unfortunate," said Turkana police chief Ronald Opili.The Kenya Red Cross said it had evacuated those injured in the school attack by plane for emergency treatment.Turkana, an arid region bordering South Sudan, is awash with small arms and violent clashes between competing communities over resources and territory are common, as is armed raiding of cattle and livestock.