The twins were arrested on the corner of Leyds and Twist streets after their uncle told police they had committed a murder, said Warrant Officer Xoli Mbele.
They led police to an accomplice who was also taken into custody.
“The twins told their uncle that they wanted money to go to Zimbabwe because they have killed someone.”
Four men robbed and stabbed a 30-year-old man on the corner of Claim and De Villiers streets on Monday.
“He was stabbed once in the upper body and paramedics certified him dead on the scene.”
The robbers escaped with his cellphone and R40.
The arrested men, aged between 19 and 24, would appear in the Johannesburg Magistrate’s Court soon, said Mbele.