Police documents were deliberately classified to hamper or hinder Crime Intelligence investigations, a senior Hawks investigator told the state capture commission of inquiry on Tuesday.
Colonel Kobus Roelofse was testifying about events that occurred from March 2011 to date.
"You cannot use classification to hide criminality. This is my assertion. Documents were classified.
Roelofse told the commission that the refusal to declassify documents frustrated his investigations over the past seven years.
"In those cases, those who were involved [in criminality] are the ones who classified the documents," he said.
"It became evident that it was being used to cover up maladministration. Therefore, in my view, many of [the documents] were incorrectly classified and since May 2012, management of SAPS (SA Police Service) have refused to supply these documents," he said.
Evidence leader, advocate Veruschka September, asked Roelofse why police documents were classified.
"For various reasons. But more importantly, to hide the identity of agents as well as informers, and also not to divulge the physical addresses of safe houses and business addresses within the SAPS (SA Police Service) environment," he responded.
"Who would have the authority to declassify or classify documents?" September asked.
"The author of the document would have the authority to classify or declassify - or the national commissioner," he said.
Roelofse said there were four levels of classification: restricted, confidential, secret and top secret.
"Just to clarify, I am not here to ask the commission to help me declassify the documents, I am just here to tell you what happened and what needs to be rectified," he said.
Roelofse was the lead investigator in a case in which former Crime Intelligence boss Richard Mdluli was found guilty of charges relating to the 1999 kidnapping and assault of Oupa Ramogibe - the man who married his ex-lover.
He was also expected to delve into the illegal activities of senior, highly placed Crime Intelligence officers.
The inquiry continues.