The army said the body was later exhumed and reburied somewhere else by the killers, according to the information provided to it by some of the arrested suspects.
According to the army, the shallow grave was confirmed by four independent sources in the community and also by sniffer dogs.
It was gathered that the shallow grave reports that there is a distance of one kilometre between the main road and the location of the grave.
Mr Alkali was the immediate past chief of administration of the Nigerian Army. He was declared missing on September 3 when he was traveling from Abuja to Bauchi State. He is believed to have been killed by his abductors.
On Friday, a major general, B. A. Akinruluyo, the General Officer Commanding, 3 Division, Rukuba Barracks, narrated how the shallow grave was discovered.