The 26-year-old man was caught on Tuesday afternoon at the corner of Miriam Makeba and Bree streets, said Warrant Officer Xoli Mbele.
He and an accomplice apparently tried to rob the prosecutor in his car when he had stopped.
“He was approached by two males, one came into his passenger door while his accomplice came to a driver’s door.”
His window was half open and they demanded his cellphone at gunpoint.
Mbele said the prosecutor got out of his car, chased the men and caught one of them.
“Police who were not far away came and took the suspect to Johannesburg Central cells.”
The man would appear in the Johannesburg Magistrate’s Court soon, she said.