QUETTA: A police constable was killed in a hand grenade attack on a police checkpost here on Thursday. Unidentified militants hurled hand grenade on a police checkpost in main bazaar killing constable Abdul Latif and injuring another one. After the attack, police personnel rushed to the site and shifted the dead and injured to a hospital. Police contingents also cordoned off the area and launched a search operation to apprehend the culprits.