A radical Islamist sect was behind the killing of three people in northeastern Nigeria, the latest in a spate of attacks in the last week, a police spokesman said on Wednesday. The three victims, including a senior police officer, were killed on Tuesday when men fired shots in a teaching hospital in the northeastern city of Maiduguri, the capital of Borno state. "An investigation has already commenced but I can tell you that we believe the killings must have been carried out by the Boko Haram since it was their mode of operations," the Borno state police public relations officer said. Boko Haram said on its website on Tuesday it was behind Christmas Eve bombings in central Nigeria and attacks on churches in the northeast of the country that killed at least 86 people. Source: Reuters