MASERU (Reuters) - Lesotho has detained a senior army officer in connection with the killing of the country s military leader and two other soldiers, a Defence Ministry official said Wednesday. The shooting took place at an army barracks on Tuesday, but it was not clear what the motivation was.  An army major, whose name was not disclosed, was taken into custody to help police with the investigation, Defence Ministry Principal Secretary Colonel Tanki Mothae said. The kingdom has been subject to several coups and periodic political violence since gaining independence from Britain in 1966, and South Africa called for calm after the shooting. 