MARDAN - Five rooms of the house of a former employee of a secret agency was damaged when an explosive device exploded with a big bang the other day.The incident occurred in the limits of Lundkhwar Police Station, police sources said.Sources said that unidentified persons had planted explosive device to the house of former ISI employee named Zardad Khan, son of Sheir Zada, resident of Juwar Lundkhwar. The explosives went off at 12:30 p.m. As a result five rooms of his house got partially damaged. However, it caused no casualty. The police reached the spot and collected pieces of evidence. Sources added that Zardad Khan told police that he has no enmity with any one. Police registered case against unknown people on the complaint of Zardad Khan and started investigations.