A schoolgirl was killed and six other students and a teacher were injured when a policeman opened fire at a Catholic school on May 16.
The students were getting ready to leave the school, managed by the Sisters of the Presentation of the Blessed Virgin in Sangota in Pakistan's restive Swat Valley in the northwestern Khyber Pakhtunkhwa province, when they were attacked.
Soon after the shooting angry parents started protesting outside the school and blocking the roads.
According to reports, Alam Khan, a police constable posted to Sangota Public School, built in 1962, to provide security in February, has been arrested as part of the investigation.
A day after the shooting, the Ecumenical Commission for Human Development urged the government to review the alleged security breach at the school.
As a mark of protest and respect, 12 Presentation Convent Schools in the country closed on May 17.
In 2008 the Catholic school, often referred to as Sangota Public School, was bombed by the Taliban for providing an English education to girls and the nuns were accused of converting young Muslim girls to Christianity.
The school reopened in 2012 after the Pakistan army rebuilt the institute.