Cape Town – Two armed men who killed a metro police officer in front of his Eerste River home may have been monitoring him for a while, a Cape Town official said on Tuesday.The City of Cape Town's policing and enforcement director, Robbie Robberts, said the area that Ben Koopman, 53, lived in was quiet and not really affected by gangs.His home was also in a side street.Robberts said the killing had shocked him and it felt as though he had lost a family member.Killed in cold blood"I ask myself the question, 'Why not just the take the firearm and leave the guy?' He did not even have a chance to resist them. He was killed in cold blood," he said."Somebody must have known a cop was staying there or they followed him from wherever and saw where he was staying and monitored him." Koopman was on his way to work on Monday afternoon when he was ambushed.Robberts said the uniformed officer had been walking in his yard to his car when the men walked past and he greeted them.The men apparently turned around and shot him from behind.They did not take his vehicle. According to Western Cape police, they ran off with his service pistol and hand radio.Hawks spokesperson Brigadier Hangwani Mulaudzi confirmed the murder docket was now with them.No arrests had yet been made."The matter is receiving serious attention," Mulaudzi said.RewardCommunity Safety MEC Dan Plato condemned the attack and extended condolences to Koopman's wife, three children, his friends and colleagues.The City is offering a R50 000 reward for information leading to the men's arrests.On Monday, the City's safety and security mayoral committee member, JP Smith, revealed that 71 of their officers had come under attack between January 2015 and January 2016.Robberts indicated that officers were often targeted for their firearms.The US Drug Enforcement Administration would be offering stress exposure training to 50 of the city’s metro police, traffic and law enforcement officers in the next two weeks.It was hoped that placing officers in ultra-realistic virtual reality and simulation training would equip them with the skills to react appropriately in stressful, dangerous situations.