The police's crime intelligence unit drove Boeremag members into planning a coup, a retired police spy testified in a treason trial on Thursday.
Former crime intelligence officer Captain Deon Loots testified that the rightwingers had initially planned only to protect themselves against crime.
However, the police's crime intelligence headquarters had been intent on nudging their actions towards a plan to overthrow the government.
Loots was testifying in an application for a special entry on the court record which could eventually be used on appeal, in an application to set aside the convictions of the 20 accused on a charge of high treason.
The convictions arise from a rightwing coup plot to violently overthrow the African National Congress government.
The last of the accused were arrested after a series of bomb explosions, one of which caused the death of Soweto mother Claudia Mokone in 2002.
Loots recruited JC Smit, one of the chief witnesses in the treason trial, as a police informer in 1994 and acted as his handler until the middle of 2000, when he decided to leave the police.
Loots was put on medical pension after being diagnosed with post-traumatic stress syndrome.
Smit was a member of the Afrikaner Weerstandsbeweging's Ystergarde (iron guard) and was, at that stage, an accused in a criminal trial in the High Court in Johannesburg.
He was one of the men accused of planting car bombs in Johannesburg and at the international airport in Johannesburg in 1994, but was acquitted on all charges in 1996.
He was offered "considerable compensation" for spying on the AWB during the trial and was later tasked with becoming close to certain rightwingers to gather information.
Loots gave Smit instructions and regularly sent reports to police headquarters about the information he gathered.
Loots said he finally decided he was done with the police after a confrontation with his commander at the rightwing reactionary desk in 2000.
He told Smit he was no longer with the police and that Smit would be transferred to another handler, but advised him "to get out of the whole story because huge trouble was coming".
"I came in conflict with my commander and the commanders at headquarters," Loots testified.
"They understood that I did not agree with the whole process how the investigation [against the Boeremag] was driven.
"I said it in my reports and I told them many times that according to my information it was a crime self-protection plan and not a coup.
"They saw it in a different light and drove it in a different direction.
"It has been building up since 1998, but the bomb burst in 2000," he said.
Smit was an AWB suspect in the bombings when he was identified as a possible informer.
Loots said he focused on Smit because he was young, thought that "any form of sports" would get him attention, and could be led in any direction.
The information Smit supplied eventually drew the attention of his commanders at headquarters, who realised a new movement was forming and should be investigated.
Loots arranged an "accidental" meeting between Smit and rightwinger "Oom Jan" Viljoen when he became aware that Viljoen was attending and later also addressing meetings about self-protection.
Smit started playing the role of being involved in the commando so he would be seen as credible.
Loots said that, after a while, he and a fellow investigator realised that no one would suddenly start having meetings out of the blue and that someone must have laid the basis for the meetings.
They eventually came across the file of the "Verligte Aksiegroep" (enlightened action group) at headquarters and realised there was a document that was similar to the documents being used at the rightwing meetings.
"I saw that it was a military document dealing with the restoration of law and order through the commandos after 1994.
"The document never talked about a coup," he said.
Judge Eben Jordaan postponed the trial to 25 February, when Loots will resume his evidence.