The alleged mastermind behind the robbery at the Office of the Chief Justice is expected to appear in the Randburg Magistrate's court on Monday.

There was previously speculation that Nkosinathi Msimango might be released from police custody over the weekend due to lack of evidence.

Acting police commissioner spokesperson Athlenda Mathe confirmed Msimango’s court appearance to News24 on Sunday evening.

"The SAPS [South African Police Service] remains committed to ensuring that perpetrators of crime that seek to undermine our judicial system are brought to book. The matter will be handled by the NPA [National Prosecuting Authority] going forward," Mathe said.

Msimango was arrested on Friday afternoon.

Mathe previously said Msimango has important information on where the 15 stolen computers were taken.

The computers are believed to contain sensitive information about South African judges.

But, speaking to News24 from the Boschkop police station on Friday, Msimango denied all the allegations.

"I am willing to work with police in the investigation, but it would be hard as I don’t know anything about it,” he said.

Two other suspects appeared in connection with the case in the Mamelodi Magistrate's Court on Wednesday.

They were charged with possession of illegal firearms and forged identity documents.