The official stated that the accused was known for acting out at school and that he was located close to the district's border with Uttar Pradesh.
He was also found in possession of the weapon used in the murder, Yadav said.
Superintendent of police Agam Jain stated that the deceased died immediately after the youngster reportedly used a locally manufactured handgun to shoot principal S K Saxena (55), in the head, close to the restroom at Dhamora government High School.
Only one bullet was fired, according to Aman Mishra, the city superintendent of police, who spoke to PTI.
Mishra, who was at the crime scene leading the investigation, stated, "According to the preliminary investigation, the accused was upset about being reprimanded for arriving late today as well as on previous occasions."
According to R P Prajapati, the district education official in charge, Saxena has been the school's principal for five years.
Saxena was described by the school's instructor, Harishankar Joshi, as a "gem of a person" and the accused as a "notorious lad" who attended school at his whim.
"Principal Saxena once gave these pupils advice. He would give their parents a call if nothing changed. He got along well with every employee," Joshi said.
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