'I have an obsession with Agent RS452." With these words, former ANC intelligence unit commander Mo Shaik began to detail his 13-year hunt for the spy.

He was telling the Hefer Commission on Thursday why he believed that Bulelani Ngcuka, the National Director of Public Prosecutions, was "in all probability" RS452.

Shaik said he first came across Ngcuka's name in an intelligence report about a meeting between Cosatu and the ANC. From this, he gathered that:

There was an apartheid agent with the codename PN.647, with whom Ngcuka met twice - in Oslo and Stockholm.

Ngcuka should have had his right to travel restricted, but he was issued a passport.

The report stated that Ngcuka was attached to the International Labour Organisation and was possibly "the ANC representative in Geneva". Yet the Security Branch recorded there was "no file" on Ngcuka.

The report was signed by Lieutenant-Colonel W F Viljoen, who was involved in the Pietermaritzburg treason trial, during which Ngcuka was jailed for refusing to give evidence.

Subsequently, said Shaik, he received two reports written under the name of RS452.

He cautioned that the reports did not necessarily originate from RS452 - now unmasked as Eastern Cape lawyer Vanessa Brereton - as it could have been an example of false flagging, used to protect the identities of apartheid agents.

The first report dealt with the Henk van Handel Trust, described as a front organisation for the ANC.

It seemed that the origin of the information was Geneva, Cape Town and Port Elizabeth.

Ngcuka was a trustee of the trust. His identity number was mentioned in the trust deed.

He was living in Geneva.

The report was distributed to various regions as it mentioned people who were known to be active or reside in the region, the majority of them lawyers.

A second RS452 report was about a meeting in Port Elizabeth of the National Association of Democratic Lawyers (Nadel) at which a United Democratic Front plan to "take over" Nadel was discussed.

Using the information that the source gave to the Security Branch as a basis, Shaik started the hunt.

He concluded that the agent was a senior person warranting special handling; someone from the legal fraternity involved in the Henk van Handel Trust and Nadel; and probably an ANC member in the Eastern Cape.

Shaik said he found suspicious the fact that:

Ngcuka was issued a passport after his arrest. On a document, it was stated that there was no objection to its issue "from a security point of view". This passport was later renewed.

Shaik said he also discovered "there may have been an attempt to generate a identity number for Ngcuka".

When a friend went to tell Ngcuka of the arrest of an MK cell commander minutes before, he already knew about it.

Shaik was forced underground when Operation Vula, a clandestine operation to bring ANC leaders into the country, was detected. He halted his hunt without conclusion.

Thirteen years later, when he returned to South Africa after a diplomatic assignment abroad, he said he discovered that his erstwhile commander Jacob Zuma, now deputy president, was under investigation for corruption in the arms deal.

Shaik said he knew Zuma was not involved. He therefore decided to share the contents of his database relating to Ngcuka with high-ranking officials in government.

At the end of Shaik's evidence, Judge Joos Hefer asked: "How would you rate the chance of Ngcuka being a spy?

Shaik responded: "I cannot come to a conclusion that he was not a spy."

With acknowledgements to Estelle Ellis, Jeremy Gordin and The Star.