Horak's testimony emerged before a mix of spies and former spies; their lawyers; editors past and present; journalists who had been the target of state scrutiny; and former revolutionaries who had once borne the brunt of apartheid security force attentions.
Horak said it was an international phenomenon that governments would place informers among the media as part of their intelligence-gathering operations, so it was not surprising that the tradition of recruiting journalists was continuing in South Africa.
He said state monitoring procedures had been greatly enhanced by technology and had consequently become more sophisticated. A state telephone monitoring system outside Pretoria allowed security forces to monitor any telephone conversation anywhere in the world without going near a Post Office or a telephone line.
Looking old and tired, Horak described his life as a professional police agent caught between the murderous intentions of his handlers and the media establishment.
He said his former handlers tried to assassinate him after he was finally forced out of journalism in 1985. His life was also threatened several times by his handlers when he was working for them. This had forced him to flee the country with the assistance of the ANC after he was driven out of the security forces. He was subsequently instrumetal in drawing up guidelines for the new South Africa's intelligence community.
A former journalist at the Rand Daily Mail, Horak said journalists who acted as informers under apartheid were "two-a-penny" in those days.
Horak claimed many senior editors knew of his work, but they did not take any action against him during apartheid. He singled out former Sunday Times editor Tertius Myburgh as one of the editors who had knowingly co-operated with him in his position as an informer.
He said former Sunday Express editor Ken Owen had also allowed police spy Craig Williamson to write a column under an assumed name in his newspaper.
He said he was also often approached by journalists seeking favours from him because they knew he was a police spy. These included getting passports and visas organised by the apartheid state.
Many, including an assistant Sunday Times editor, had approached him, seeking his assistance in getting into contact with the security forces so that they could work for them.
He said informers were divided into three main categories - agents who were professional policemen doing a job; informers who gave information freely or for money on a regular basis; and "sleepers", who would give information when it suited them. He expressed sympathy for journalists who had believed in what they were doing because the small pool of newspapers in South Africa meant there were few employment opportunities for alternative employment.
He accused Anglo American of cynically manipulating its expressed commitment to liberal ideas to hide its pursuit of profit.
He said the closure of the Rand Daily Mail in 1985 proved that the corporation did not care for the poor. It closed the newspaper because, like most other newspapers in the country, it was losing money.
He was adamant that everyone who worked for the SABC during apartheid had been an agent because the former Broadcasting Act had required the broadcaster to support the government. This was made clear to every person who was employed there, he said.
His testimony contained many gaps because TRC regulations prevented him from naming individuals who were still alive and working in the media, but he revealed that he had spent more than 30 hours being "debriefed" by the commission. It became clear during his testimony that the names had been given to the commission in the debriefing.