Forensic investigator Paul O'Sullivan has been released after his arrest late on Monday afternoon.
O'Sullivan brought a late-night urgent application in the High Court in Pretoria to be released.
His lawyers asked the judge to enforce an earlier high court order that police should not arrest him, but give him 48 hours to present himself to a police station, O'Sullivan's legal adviser Sarah Jane Trent told News24. He was booked into the Kameeldrift police station at 8pm, she said.
Speaking to Xolani Gwala on 702 Talk Radio on Tuesday morning, O'Sullivan said: "It's now emerged that the complainant in the case against me is a major general in the North West province called Mabula, who also arrested Gerrie Nel [when he was investigating Jackie Selebi], and Major General Johan Booysen in KZN. He is obviously a go-to guy for these sorts of issues."
In a video taken during O'Sullivan's arrest, Spies is heard reading out a high court order to arresting officer, controversial senior police officer Major General Ntebo "Jan" Mabula.
Spies said on Monday police were breaking a high court order between Police Minister Nathi Nhleko, acting police commissioner Khomotso Phahlane, and Hawks boss General Berning Ntlemeza, not to arrest O'Sullivan but grant him 48 hours' notice to present himself to a police station. Spies presented a copy of the high court order to Mabula.
Earlier on Monday, News24 reported Mabula had taken the lead in Phahlane's fight back against police watchdog Ipid, who are investigating him.
Gwala asked O'Sullivan to respond to allegations that he had impersonated Ipid officers.
"They're talking rubbish. Our meetings were tape recorded and headed by a senior member from Ipid, who made it clear he was heading it and that we were assisting. We were asked to assist and were just doing our civic duty."
O'Sullivan's lawyer, Willie Spies, told News24 that 17 police officers in seven cars arrested him outside Afriforum's offices in Pretoria and took him to the Kameeldrift police station.
Trent was with O'Sullivan when he was arrested. She said she followed police to make sure he was being taken to Kameeldrift.
Trent was arrested and held over the weekend.
Mabula has a history of being involved in politically-motivated arrests. He was a close ally of former police commissioner Jackie Selebi and former police crime intelligence head Richard Mdluli.
Police spokesperson Brigadier Sally de Beer could not immediately be reached for comment.