PESHAWAR  - A police personnel was killed and three others were injured when unknown persons hurled hand grenade at a police check-post in Pahari Pora area on Thursday evening. Sources said that the police personnel were on duty in Pahari Pora check-post when unknown persons hurled hand grenade and escaped. The attack resulted in killing of one police personnel Wahid Zaman and injuring of three others. Other injured persons were shifted to Lady reading Hospital Peshawar.DSP Sajjad Khan told journalists that unidentified assailants had hurled a hand grenade at a check-post set up near the Pahari Purah Imambargah.Police launched search action and started investigations.