CHARSADDA - The boundary wall of a government high school was completely destroyed when explosives, planted by unknown miscreants, exploded in Charsadda on Thursday night. Police said a three-kg bomb was planted by miscreants near the boundary wall of Government High School No-1, Charsadda, in the limits of Prango Police Station. They said the bomb exploded with a big bang, razing the wall to ground. Watchman of the school opened fire in the air soon after the blast, they said. They said police rushed to the site and cordoned off the area. They said the police launched a search operation, however no arrest was made till filing this report.