The brutal murder of Daniel Morgan shocked Britain in 1987.
Horrified police found his body with an axe embedded into his skull in a South London car park.
Now, 33 years on, Channel 4 documentary Murder in the Car Park investigates who killed Daniel Morgan.
Who killed Daniel Morgan?
Police still do not know who killed Daniel Morgan.
An assassin killed the 37-year-old father of two died by taking an axe to his face four or five times.
Cops have arrested the same people for his murder many times over the last three decades.
None were ever convicted.
Cops ruled out that the motive was a robbery gone wrong as the £1,000 wad of cash Daniel was carrying hadn't been touched.
Another clue that the murder was premeditated is that two sticky plaster strips were found on the axe handles so that fingerprints couldn't be used as evidence.
In 2007, the Met announced that the motive for murder was that Daniel "was about to expose a south London drugs network possibly involving corrupt police officers."
Who did police arrest for killing Daniel Morgan?
Cops arrested six men on suspicion of murder – including two police officers.
Daniel's former business partner Jonathan Rees was one of the suspects under investigation.
Police also arrested brothers Glenn Vian and Garry Vian as well as a builder named James Cook on suspicion of murder.
But they were all found not guilty.
The courts awarded £414,000 in damages to the three men afterwards.
Jonathan and Glenn received £155,000 each, and Garry won £104,000.
All three feature in Murder in the Car Park to give their thoughts on who the killer is.
"For someone to not leave a fingerprint or DNA or anything like that...," retired secret guard Glenn says in the documentary.
"Back in 1987, people only knew about fingerprints.
"How would you know not to leave any evidence about? Well, a police officer would – wouldn't he?"
Are cops still investigating the Daniel Morgan case?
The Home Office is now overseeing the case after five failed police inquiries.
Cops have since admitted their investigations were hampered by corruption.
In 2013, then Home Secretary Theresa May launched an independent panel – the Daniel Morgan Independent Panel – to review how police handled the investigation.
"The horrific murder of Daniel Morgan...was dogged by serious allegations of police corruption," she said at the time.
"Several criminal investigations failed to bring those responsible to justice.
"This independent panel will leave no stone unturned to find out why."
Retired Court of Appeal judge Sir Stanley Burnton is chairing the independent panel.
He said: "The family of Daniel Morgan, Daniel Morgan himself and the British public have been badly let down by the criminal justice system.
"I am determined to do everything I can.
"As chair of the independent panel, to uncover the facts, the circumstances and the truth behind the previous failed investigations."
The Home Office inquiry will review how police corruption impacted the murder investigation with a report expected later this year.
What happened to Daniel Morgan?
Daniel was a private investigator who owned his own agency, Southern Investigations, in Thornton Heath.
According to the Guardian, he was looking into police involvement in drugs networks across London in the lead up to his death.
On 10 March 1987, Daniel was killed after he was struck in the face with an axe.
Cops found his body in The Golden Lion pub in Sydenham, south east London, on 10 March 1987.
There were no witnesses.
He was just 37-years-old at the time.
Daniel left behind his wife Iris, daughter Sarah and son Daniel.
His brother Alistair has led the campaign into getting justice for the family.
"Daniel’s murder, the police corruption and the ensuing years of failed investigations have been agony for the whole family," he said.
"[My brother's] children have grown up without a father and my mother is now 86 years old.
"We need to know the truth about what happened to Daniel and why."
What is Murder in the Carpark?
Channel 4 docs-series Murder in the Carpark looks into the mysterious circumstances around Daniel's death.
The three-part series will explore the shocking theories involving police corruption, phone hacking and covert operations.
It will also include interviews with Metropolitan police detective Sid Filler and Daniel's brother Alistair.
Produced by Indefinite Films, the documentary was four years in the making.
Murder in the Carpark is on Channel 4, Mondays at 9pm.
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