Police confirmed that the Interpol offices in Pretoria were broken into and laptops and other electronic items were stolen.
"We have registered a case of robbery. Several items were taken, including laptops, cameras and tablets," police spokesman Lt-Gen Solomon Makgale said.
"Some items belong to the state and some were privately owned by people who work in the office."
According to the Sowetan newspaper, the laptops contained information about Czech fugitive Radovan Krejcir's case, secret witness lists, and information linked to investigations into international crime syndicates.
Investigators apparently indicated that one of the stolen laptops belonged to an officer involved in George Louca's extradition to South Africa from Cyprus.
"That's what they say. That is pure speculation," Makgale responded.
"We are busy with an investigation to establish a number of things. We would like to establish what was contained in the items taken."
Makgale could not tell Sapa if access cards and key codes had been used, or if the building was monitored by CCTV cameras.
"We still need to investigate how this could have happened," he said.
No arrests have been made.