Joao and Jose were fatally shot when a group of more than five men entered the busy butchery and supermarket, purporting to be customers, before opening fire on the business men in front of shocked staff.
An inconsolable Pedro de Abreu claimed it was the same gang that had previously terrorised his family.
"They attacked the shop on December 31. We fought back and they started shooting. They later ran away before taking away any money. It is the very same group that came in today," Pedro told the African News Agency (ANA) .
"Two weeks after the December 31 incident, I had another encounter with them. They were now dressed as police officers. They pulled me off as I was driving on the R21. They took my car and drove me around. They could not find any money. I didn't have money so they let me go."
Pedro was not in the shop when the gang pounced on Monday. He said other family members were struggling to come to terms with news of the double murder.
"We have been together in business for 30 years now. Our family members are taking it very badly. The pain of it is unimaginable. These were my brothers," said Pedro, fighting back tears.
A security guard told ANA the robbers made off with an undisclosed amount of money after shooting the shop owners. He told ran to get help at a nearby police station, at the Bosman bus and train station.
"I got there out of my breath from the sprinting. I told them that we have just been robbed and one police officer who was in a white shirt, who appeared to be their senior, instructed three officers who were standing outside to come with me. I was surprised when they said it is not their job to respond to robberies. They said I must go to the Pretoria central police station," he said.
"I was confused. How can police officers send me away when I was calling them to pursue criminals? I knew at that time that people had been killed. The police encouraged me to call 10111. I called the Pretoria central officers and they came instantly."
He said a pistol had been held to his head during the robbery. "After the boss [Joao] opened the shop, he told me to install the small steps for customers at the entrance. Soon after, the lady at the counter started screaming, telling me to look at the entrance. An armed man grabbed me and kicked me. I fell down. He said he would kill me if I tried to rise up. He was pointing a gun at me," he said.
"Soon after, shots went off in the shop. The ordeal took around five minutes. When the robbers were gone, that is when I rushed to the police station at Bosman."
Spokesperson for the Tshwane West police cluster, Captain Augustinah Selepe, said the claims would be investigated.
"We are not aware of such allegations that the security guard was turned away by the police. On my arrival at the scene I found all role players, including police from the Bosman station. We will investigate those allegations," said Selepe.
Earlier, Selepe said the shop owners were gunned down before an undisclosed amount of cash was stolen at the busy shop at the corner of Paul Kruger and Scheiding streets.
"Business robbery and two murders were reported today [Monday] at about 06h05 at Blou Bul Meat and Fish Market, in Pretoria Central. Our preliminary investigations reveal that five suspects entered the Blou Bul butchery with pretence of buying. They immediately pointed the victims [the business owners and staff] with firearms inside the butcher and killed the two brothers," said Selepe.
"A brown box with an undisclosed amount was taken by the suspects. One of the video footage shows that the suspects were using two vehicles – one Silver Grey Mercedes Benz and a white Mercedes Benz."
Selepe appealed to members of the public to assist in the ongoing investigation to find the suspects. The shop was closed off Monday.
Members of the non-profit organisation, The Portuguese Forum, were inside the shop with some family members of the business owners.African News Agency