Senior police detective Frans Mathipa had been fighting for four months to gain access to a crucial piece of information in the case he was working on. Finally, he was told, it was going to come his way.

But he feared his pursuit of it could cost him his life.

Two days later, his car was found overturned – he had been shot dead while driving.

Now seven members of South Africa's special forces, and one military police officer, have been charged with murdering Lt Col Mathipa, a highly respected officer, in August 2023. They deny the charges.

There has been no date scheduled for their trial, and there are concerns it will never go ahead, because three of the men charged with his murder have refused to comply with a court order revoking their bail. They are still working for the army's special forces, and one of them has been promoted.

The case has caused consternation in one of Africa's most robust democracies, with fears the country's military is significantly overreaching its mandate.

We asked the South African army whether it was responsible for Mathipa's killing. It did not respond.

Several hundred pages of secret police and court documents, shared with the BBC, set out the evidence suggesting special forces killed Mathipa – who worked for an elite police unit known as "The Hawks".

We have also interviewed key sources in the police investigation – South Africa's former head of counter-terrorism in The Hawks; Mathipa's commanding officer; and Mathipa's family - to build the most comprehensive public account of the events leading up to the detective's death.

It presents a compelling case that South Africa's special forces are responsible for his murder.

In particular, police documents show that the vehicle that trailed Mathipa just before he was shot was registered to a front company for the special forces. And that tracking data found in that vehicle puts it at the scene of the shooting.

One of the men in the car, Maj Sunnybooi Wambi, the documents show, was also spotted at the scene of an alleged abduction carried out by special forces soldiers – the case that Mathipa had been investigating.

After Mathipa's death, special forces issued a chilling warning to The Hawks, the police documents say. "You can appoint 10 investigating officers; we will kill all of them," said the warning, according to police.

Investigations centred on an Ethiopian man called Abdella Abadigga, an alleged so-called Islamic State [IS] militant. He had been granted temporary asylum in South Africa in 2008, but was arrested abroad in 2017.

Abadigga had then been smuggled back into the country, by the South African military and Department of Home Affairs, to be used as an intelligence asset - but had "gone rogue", according to Col Tollie Vreugdenburg, former head of counter-terrorism in The Hawks.

Abadigga had gone on to extort Johannesburg's Ethiopian neighbourhood, sources in the community told us. This money was used to fund IS, says the US government.

We asked the South African army if it had facilitated Abadigga's return to South Africa. And we asked the Department of Home Affairs if it had lied about a planned deportation of him to Ethiopia, and had instead smuggled him back into South Africa on an expired passport and refugee permit. They did not respond.

Specifically, Mathipa was investigating the allegation that special forces had then gone on to abduct and kill Abadigga in December 2022 - who the United States, earlier that year, had put under sanctions, designating him an IS recruiter and fundraiser, as well as a trusted supporter of Bilal al-Sudani, a top IS figure in Somalia.

Court documents show that after Abadigga's abduction, his phone connected to a mast near a military base. Police sources say it was used to call a number in Somalia.

The Pentagon did not respond to the BBC's question on whether Abadigga's phone helped locate al-Sudani, who was killed by US special forces in Somalia in January 2023, only a few weeks after Abadigga's alleged abduction.

We also asked South Africa's President Cyril Ramaphosa whether Abadigga had been kidnapped at the behest of the US. He declined to comment.

When Mathipa was assigned the case, four months before his own death, he already knew special forces were implicated, but he was trying to secure more evidence.

He was building on information already gathered by Abadigga's brother, Ameen - who had opened a missing person's case soon after the disappearance, and had been assigned an investigating officer (IO) from local police.

He and the IO had obtained CCTV footage showing the last known movements of Abadigga and his bodyguard Kadir Abotese at the Mall of Africa, a shopping centre on the outskirts of Johannesburg.

The footage, clips of which the BBC has seen, shows a man in a blue top following Abadigga and his bodyguard as they leave the food court to head back to the car park, and paying for parking three seconds after Abadigga and Abotese do.

The mall CCTV footage contains another vital clue. The licence plates of the suspected kidnappers' vehicles are clearly visible.

At the time of Abadigga's disappearance, PCT's directors included Maj Gen Herbert Mashego, the then commanding officer of 5 Special Forces Regiment.

Police documents say a meeting was arranged between the IO and high ranks of the military, including Brig Gen Yalo, the then head of special forces, at which the IO was instructed to tell Ameen there was no link between PCT and the military.

So, with the investigation seemingly at a standstill, Abadigga's brother took his case to the Johannesburg High Court.

Responding to Ameen's legal action, special forces denied all knowledge of Abadigga or his whereabouts. They did, however, admit their soldiers had been at the Mall of Africa on the date in question, but said they had been there for a training exercise.

They named the man seen wearing blue on CCTV as Maj Sunnybooi Wambi, and said he had been the exercise commander. They also admitted all the suspect vehicles seen at the mall belonged to them.

Domestic operations by South Africa's military need to be authorised by both the government and the presidency.

We asked South African former Defence Minister Thandi Modise, and President Ramaphosa, if they had authorised a training exercise in the Mall of Africa - Modise did not respond and Ramaphosa declined to comment.

When access to these documents was finally promised, three months later, Mathipa had a premonition that he would be murdered - according to Brig Paulina Sekgobela, his commanding officer.

"When [Mathipa] left my office he said: 'Brigadier, you know, these people - they are going to kill me. I'm going to die'," she told the BBC.

On the day Mathipa was killed, he was phoned by a man calling himself Tebogo, who claimed he had information on the case for the detective - according to Mathipa's daughter Basetsana, who was home with him at the time.

Mathipa and Tebogo arranged to meet at a petrol station in Pretoria.

When Tebogo failed to show, Mathipa drove away again, along the highway.

He was killed while driving, by rounds fired from high-velocity weapons which special forces would have had access to, according to South African police.

And footage from motorway toll gantries, police say, shows one of the occupants of the black BMW, which tailed Mathipa moments before his murder, was Maj Sunnybooi Wambi.

This car, like the three vehicles connected with Abadigga's disappearance at the mall, was registered to PCT, they add.

New detectives were assigned to the case after Mathipa's death, triggering a chilling message from special forces, that made its way to the police's Criminal Intelligence division.

Police say it warned that, however many investigating officers were assigned to the case, "we will kill all of them".

Twelve members of the South African military have been arrested in total, including Lt Col Sunnybooi Wambi, and the current head of South Africa's special forces, Brig Gen Solomon Lechoenyo - both promoted to these positions since police first started investigating their roles in the case.

The 12 have been variously charged with the abduction and murder of Abadigga and Abotese, the murder of Mathipa, fraud, and obstruction.

All deny all charges and they were initially released on bail. But six of them later had their bail revoked, and were ordered to turn themselves in to custody.

Three of the six, including Wambi, have been charged with both Mathipa's murder, and Abotese's abduction and murder.

July, their lawyers cited mental health treatment for their absence. Three years after Mathipa's killing, no trial date has been set.

Meanwhile, Abadigga's body has never been found.

was barking up the right tree. He was taking on the right lion," Vreugdenburg says of the late detective.

Mathipa's daughter Basetsana puts it starkly: "We need justice. I'm never going to see my dad anymore... Why my dad? Because he was doing his job." (BBC, but headline reworked)

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