Sepoy Ritender opened fired on his fellow colleague Sepoy Mukesh Tiwari at Rashtriya Rifles Unit in border belt of Kala in Noushera sector of the district during the intervening night of May 27-28, PRO Defence S N Acharya said.
Tiwari, resident of Allahabad, was killed on the spot, he said, adding that a court of Inquiry (CoI) has been ordered into the incident.
After the incident, Ritender has been arrested by the army officials and is being questioned.