According to a military source President Buhari was alarmed when he learnt of the Gashigar attack on troops.
It was gathered that the investigation followed the October 22 attack on troops' location in Gashigar town in Borno State.
Media reports had claimed that 83 soldiers went missing in the attack while some were killed by the Boko Haram terrorists, but the army denied the reports.
A statement by the army spokesman, Sani Usman, had said 13 soldiers were wounded during the surprise attack and admitted that some soldiers were missing without giving any figure.
Sources says President Muhammadu Buhari and the Chief of Army Staff Lt. Gen. Tukur Buratai, were alarmed by the attack, which involved an entire unit.
"The President was furious and discussed the matter with the COAS when some of the heads of that units were ambushed by the Boko Haram," a military source told Punch.
"The Army leadership took out time to screen the communications lines of the officers for several days without making it known.
"The suspicion was that they have links with some civilians and the links were traced. They are giving them vital information concerning the movement of soldiers.
"How come that the Borno State Governor and other officials have not been attacked, yet they ambushed the Chief of Army Staff. They have not attacked civilians but they attacked the COAS."
The suspects will be tried according to military laws.