KARACHI- Two people, including a policeman, were killed and one person was reported injured in an attack on a police checkpost in Karachi. The gun attack took place in the city's Garden Town near the Karachi zoo when unknown attackers opened fire on the checkpost. A policeman and a security guard of a private bank died on the spot while a passerby was injured in firing. Reports said police returned fire immediately but the attackers managed to flee from the scene. The injured were shifted to civil hospital for medical treatment.