Johannesburg - A police officer has been killed in the Johannesburg area during a robbery in Themba on Thursday morning, Gauteng police said, bringing to two the number of policeman killed in the line of duty this week.On Wednesday, a 36-year-old police officer at Vosloorus Crossing was killed during a shootout with robbers. On the same day, in the Western Cape, a member of the Hawks was stabbed to death after he stopped on the N2 to inspect damage to his car.On Thursday morning, two officers were attending to a business robbery in Sekampane section when a shoot-out ensued between them and the suspects, Lieutenant Colonel Lungelo Dlamini said.The 35-year-old officer was shot and wounded and rushed to hospital, but he died on arrival.His colleague was not injured.One of the robbers was also shot and killed during the shootout. The second suspect, who was in possession of the gun, managed to escape on foot and was still at large, said Dlamini.The suspect who died on the scene was identified as 26-year-old Oupa Chauke.Groceries believed to have been stolen from the shop were found at the scene.Search for suspectsMeanwhile, Dlamini said police were still looking for a gang of armed robbers who shot and killed a 36-year-old police officer at Vosloorus Crossing on Wednesday morning.A group of about six suspects fled the scene with two vehicles, a silver Nissan Tiida and white Audi A4. A Nissan Tiida was found abandoned at Vosloorus extension two.Police are looking at the CCTV footage to identify the killers.Gauteng police commissioner Lestja Mothiba called on communities to rally around the police in an effort to deal with criminals who were killing officers."Police are attacked by highly armed gangs and any information that may lead to the recovery of these firearms will be rewarded."The Hawks said five people have been taken in for questioning following the death of a top police officer in the Western Cape on Wednesday morning.Warrant Officer Petrus Holz, 50, was stabbed to death on the N2 near the Macassar turn-off, Hawks spokesperson Brigadier Hangwani Mulaudzi said.He said Holz, who was a member of the commercial crimes unit of the Hawks, had stopped his car to check if "everything was okay" after debris was strewn across the road.Western Cape police said Holz was in an unmarked car and in civilian clothing when he was attacked.