Quetta - Four people including a police head constable were killed and seven others injured in different incidents of firing and road mishaps in Khuzdar, Turbat and Quetta on Sunday. According to reports reaching here, unknown armed assailants opened indiscriminate firing on a head constable Ahmad Khan in Karkh area of district Khuzdar and escaped from the scene. As a result, the head constable died  on the spot. In another incident in Quetta, unknown armed persons shot dead a person at Sariab Road. His name was identified as Ghulam Mustafa Shah. The deceased was a retired teacher. The cause of his killing could not be known. Moreover, Unknown armed persons opened fire on a person on Airport Road Quetta and fled the scene under cover of firing. The injured was rushed to the hospital. His name was identified as Bismillah Khan. The cause of attack was stated to be result of an old enmity. Meanwhile, a pickup which was on its way to Turbat from Mand turned turtle and plunged into a deep gorge, resulting spot death of two persons namely Din Muhammad and Pir Muhammad. Six others also injured in the incident. The injured were taken to the nearby hospital.