Correctional Services said that “matters are under control” at Johannesburg’s Sun City Prison on Wed.
Another Coin Security depot, the third in three months, was hit at the weekend, and it is believed R7million was stolen this time.
Sowetan was reliably told that this robbery at the beleaguered company's Witbank depot was carried out by a number of men who gained entry by pretending to be policemen on Sunday morning.
"They told the guards they were coming to investigate a previous robbery. Once inside they pulled out their weapons and held the staff hostage," said the source.
The source said one of them drove a vehicle on to the property and then they loaded all the money from the safe.
Coin's Mark Celcraig said they were still investigating and he could not comment yet.
Police spokesman Superintendent Izak van Zyl confirmed the robbery. He said about 14 to 16 men stormed into the depot at about 10am.
"One of them was wearing a police uniform and others were in private clothes and Coin Security uniforms," said Van Zyl.
Van Zyl said the security company was still counting how much money was taken. He said they had taken in one suspect for questioning, but no one had been charged yet.
The heist at the weekend comes a few days after Coin's West Rand depot was hit for R30million. A number of men damaged the alarm system and entered the building where they drugged a guard on duty.
A month previously, the company's Modderfontein depot was attacked by robbers who posed as security guards. They stole R50 million.
They allegedly entered the premises in a security vehicle which they had ambushed earlier in the day.