Johannesburg - Police were looking for a group of about 12 men who allegedly shot and killed a constable following an attempted robbery at Johannesburg's Park Station on Tuesday.Police were alerted by a security guard of an imminent armed robbery around 05:00, spokesperson Mack Mngomezulu said.The fleeing suspects confronted the officers."Others fled the scene in a Corsa bakkie while others fled on foot. Police officers gave chase. While pursuing the suspects on foot, several shots were fired at the police officers and one was shot in his upper body."A police officer, in his late twenties, was shot several times in the upper body and died on the scene," he said.The constable's service pistol was stolen. His name could not be revealed as his family had not yet been informed.