The M&G's two sources say Mphego first showed Zuma the recordings at a friend's home in KwaZulu-Natal before arranging to have them handed over to his lawyer. This was at the time Zuma was preparing to appeal his corruption case at the Constitutional Court.

The M&G was told that Mphego flew to KwaZulu-Natal and played some of the recordings to Zuma at a house apparently occupied by a long-time Zuma associate, Erwin Ullbricht. The recordings are encrypted and, to be played, require highly sophisticated and restricted software, which Mphego provided.

It is understood that a car was arranged to pick up Mphego at the airport and he flew back to Johannesburg on the same day.

Ullbricht likes to refer to himself as Zuma's adopted son and signed the lease to rent a house in Durban for one of Zuma's wives, MaNtuli.

When the M&G asked Ullbricht about the events, he said he lived in Johannesburg. When asked whether he had any properties in Durban, he said: "Don't you guys have anything better to do? You are really being petty."

Ten minutes later he called back and denied that he was the person we spoke to, although he was calling from the same number. He introduced himself as "the real Erwin Ullbricht" and said the matter in question was highly delicate, but added "I do not know what you are talking about".

He later sent an SMS saying: "Madam, you are causing war which is not actually called for. Think about that …"

The M&G's sources say Mphego made arrangements to drop the recordings and software with Hulley during the meeting with Zuma and the M&G understands that this was done at Hulley's office a few days later, although Mphego was not present.

Mphego's criminal case was struck off the roll last week by magistrate Fatima Khan. It was being pursued by Gerrie Nel, the former Gauteng boss of the Scorpions.

Mphego was accused of defeating the ends of justice for allegedly obtaining an affidavit from drug dealer Glenn Agliotti in support of former police boss Jackie Selebi. But after Nel's prosecution team was removed from the case, it was struck from the roll because the NPA was not ready to proceed.

The M&G revealed last week that NPA boss Menzi Simelane had instructed Gauteng's acting deputy director of public prosecutions, Gladstone Maema, two months ago to replace Nel.

'Dark horse'

Meanwhile, a third source who has senior-level insight into police intelligence said it was Mphego who controlled access to the decryption keys on the recordings that would make them accessible.

The code used to protect the files is an extremely sophisticated encryption key that could be accessed only with Mphego's authorisation.

Another former senior colleague said: "That chap has always been the dark horse behind Zuma."

The leaking of the recordings was investigated by the inspector general of intelligence, Zolile Ngcakani, who delivered a report to the joint standing committee on intelligence in December last year, shortly before his retirement.

The report is still being considered by the committee behind closed doors, but media reports suggested it pointed fingers at the police without being able to blame a single individual.

The timing of the leaked tapes was central to Zuma's efforts to win last year's elections, which were held 16 days after the charges against him were dropped.

At the time the charges were dropped, then-acting national director of public prosecutions, Mokotedi Mpshe, said the decision was not based on the actual merits of the case, but an abuse of process by McCarthy. At a press briefing, Mpshe quoted from phone recordings between Ngcuka and McCarthy, discussing the timing of re-charging Zuma.

The conversations took place shortly before the ANC's Polokwane conference in December 2007, where Zuma was elected the new leader of the party.

During references to high-profile people, Ngcuka and McCarthy used code names such as "Ouboet" for Selebi, "Oujan" for Zuma, and "No1", "the fellow" and "the man", when allegedly referring to former president Thabo Mbeki.

But the most damning transcript is of an SMS conversation between McCarthy and a private intelligence member, known only as Luciano, on a "political solution" to the Zuma case.

In another development, the M&G has also learned that one of the last acts of Tim Williams as the acting police commissioner was to hand over copies of the recordings, including the ones that Zuma had, to Selebi.

Selebi's lawyers made an application to Williams to declassify the information used in the corruption trial, but the recordings were never used in evidence.

The M&G Centre for Investigative Journalism, supported by M&G Media and the Open Society Foundation for South Africa, produced this story. www.amabhungane.co.za