A union of cell phone sellers and repairers is accusing a soldier of killing their leader, a rare public protest against Nigeria's military.
An Associated Press reporter said protesters marched to an army barracks Thursday to demand justice for the death of the cell phone market chairman known as Umar Quality.
Military spokesman Lt. Col. Hassan Mohammed says it is investigating and that, if found guilty, the suspected soldier will be disciplined.
The military's presence has been pervasive in the northeastern city of Maiduguri since June, when a special taskforce was deployed to fight a radical Muslim sect responsible for a rash of killings.
But residents have complained about abuses, at one time asking for the force's complete withdrawal.