Wouter Basson, dubbed Dr. Death faces a medical ethics board this week that could cancel his medical licence for producing chemicals used in numerous crimes.
Basson, now a cardiologist in Cape Town, has been acquitted in two of the highest profile trials of the post-apartheid era, where he was charged with assassinating opponents of the white-minority state, making illegal drugs and trying to sterilise blacks.
The Health Professional Council, which began hearings on Monday, was trying to determine if he sought to weaponise mortar bombs with teargas, make cyanide capsules available to spies and provide drugs to disorient kidnapped people, according to the council's charge sheet.
Basson has maintained he was fulfilling his duties to the state, did not participate in killings and has not violated medical ethics.
His opponents have argued that his actions when heading the apartheid government's chemical and biological weapons programme known as Project Coast make him unfit to practise medicine.
Dastardly in its concept and execution, Project Coast was a reflection of the inherent evil of apartheid, Desmond Tutu said in a 2002 report by a U.N. agency. Tutu headed South Africa's Truth and Reconciliation Committee, which investigated apartheid-era crimes.
Project Coast developed chemical and biological agents designed to control, poison and kill people within and outside South Africa, said the report by U.N. disarmament researchers.
The list of bizarre activities Basson was alleged to have been involved in reads like a spy thriller, including inventing gadgets such as screwdrivers concealing hypodermic needles and cigarettes laced with anthrax, according to court documents.
Basson kept a black mamba, one of the world's deadliest snakes, in his office to extract its venom. His laboratory was also said to contain whisky spiked with herbicide, chocolates poisoned with botulin and explosive washing powder.
Apartheid regime spies on Project Coast missions were accused of using toxins to paralyse or incapacitate opponents overseas and then dumping them from aircraft into the sea while still alive, the U.N. report said.
Spies were also suspected of drugging jailed activists with sleeping pills, attaching explosives to their bodies and detonating the charges, it said.
Basson's first major trial, which began in 1999, quickly fell into controversy when the prosecutor called for a new judge after the presiding justice said it wouldn't take much to convince him that Basson was innocent. Many key witnesses called by the prosecution refused to testify.
Basson was then acquitted in 2002 of multiple murders, drug-trafficking, fraud and theft after one of the longest trials in South African history. He later said he had no regrets and suggested the accusations were misdirected and exaggerated.
Basson denied responsibility for political assassinations carried out by agents using his toxins and said he was only following orders from senior government members.