As the 20 year anniversary of the murder of TV presenter Jill Dando nears, her killer remains at large.
On the morning of April 26, 1999, the 37-year-old Crimewatch presenter left her father's home in Chiswick and returned to her house in Fulham.
When she arrived shortly after 11.30am she was grabbed from behind and shot once in the head.
The BBC Breakfast News presenter was found 14 minutes later and declared dead on arrival at Charing Cross hospital.
In the past week, former Met Detective Chief Superintendent Hamish Campbell admitted the mystery was unlikely to ever be solved, with his doomed probe into the crime leading to one conviction which was quashed in 2008.
Gunshot residue found on Barry George's coat would be proved inadmissible as evidence seven years after he was jailed for the crime.
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He was freed in 2008, renewing interest in a case that continues to confound investigators two decades on.
“We, as an investigation team, brought somebody before the courts and that’s what we had to do," Mr Campbell explained in BBC One documentary 'The Murder of Jill Dando', which airs on Tuesday.
“The outcome is entirely out of our hands. You’re either guilty or you’re not guilty. It’s not really determining whatever you mean by innocence.”
Asked if he thought somebody would come back to court over the matter, he said: “Probably not.”
Mr Campbell also discounted the idea that a new person would be brought before the courts.
He added: “There’s always been the view, in the media and elsewhere, that the police chose Barry George somehow as a scapegoat and for want of a better word, a patsy, for the investigation team because we couldn’t solve it.
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“That is somewhat insulting and completely untrue, and wrong. If none of the things [about Barry] had emerged, he would never have been charged at all.”
With interest in the case rising once again, we look at the six theories about who was behind her death.
Gangland killing
One of the first theories to gain traction focused on Dando's job presenting Crimewatch .
Some speculated that her visible role on a show that had led to countless criminals ending up behind bars made her a target.
In a 2017 ITV programme, fuel was poured on this conspiratorial fire when an anonymous hit man told investigative journalist Mark Williams-Thomas that he knew who the killer was, before refusing to give a name for fear of retaliation.
The nature of the killing sheds doubt on the hit man theory however.
The fact the killer left a spent cartridge at the scene - which was a visible location with no easy escape route - and didn't use a silencer, does not scream professional assassin.
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Paedophile ring
Some have argued that Dando did indeed make enemies in the wrong circles..
According to an anonymous source who came forward years after the killing, Dando was attempting to expose a VIP paedophile ring at the BBC.
When bosses at the corporation got wind that she was sniffing around they decided to take action, the theory goes.
The source said: “I don’t recall the names of all the stars now and don’t want to implicate anyone, but Jill said they were surprisingly big names.
“I think she was quite shocked when told about images of children and that information on how to join this horrible paedophile ring was freely available.
“Jill said others had complained to her about sexual matters and that some female workmates also claimed they had been groped or assaulted.
“Nothing had been done and there seemed to be a policy of turning a blind eye.”
The BBC has said there is no evidence to support these claims.
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Stalker
Dando's time in the limelight and large following led police to question whether a member of her fan base had been responsible for her death.
Around 140 people who were 'obsessed' with the star were identified by police, including those who had sent her sexually explicit fan mail.
Shortly before her death, Dando's engagement to obstetrician Alan Farthing had been made public, leading to speculation that a crazed admirer could have been pushed over the edge.
This theory was largely discounted when none of the 140 nor any of Dando's ex-boyfriends were found to be in Fulham on the day.
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Kosovo War
In the months leading up to Dando's death Nato forces were bombing Serbia as part of the Kosovo War.
Three days before the assassination a British bomber had hit Radio Television Serbia and killed 16 members of staff.
A man with an Eastern European accent who called BBC HQ the day after Dando's death backed up suspicions that it was a revenge killing.
His warnings that BBC News chief executive Tony Hall was next on the list were taken seriously.
In 2012, Branka Prpa, the widow of a prominent Serbian journalist called Slavko Curuvija, said Dando had been targeted because she had presented an appeal urging support for Kosovan-Albanian refugees.
Her husband had been shot dead outside his home in Belgrade 15 days before Dando's murder, leading Prpa to believe there was a link.
The theory has been questioned by BBC World Affairs editor John Simpson, who has argued Dando's tenuous connection to the conflict was unlikely to have singled her out.
He has suggested his work covering the Nato bombing in Belgrade made him a much more obvious target.
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Joe the barman
Another theory finds further motivation for the killer in Dando's Crimewatch work.
In 1996 Kenneth Noye was sentenced to life in prison for a 1996 road rage killing with the help of a Crimewatch appeal.
According to a report from the now defunct National Criminal Intelligence Service, a barman called Joe owed Noye money and may have opted to settle his debts by targeting Dando.
The report said: “Joe runs a bar in Tenerife, frequented by leading ex-pat criminals. He's described as a frustrated gangster reputed to owe money to Kenny Noye. There’s been talk Joe has been keen to rehabilitate his reputation with gangster creditors.”
It does not seem that Joe was ever traced.
The IRA
One final theory again argues that Dando was targeted for her Crimewatch job, but this time the establishment did track down the killer.
Wayne Aird, who was serving a life sentence in prison for killing a man two months after Dando was shot, reportedly confessed to being part of what he said was an “establishment cover-up”.
He claimed the IRA was responsible for Dando's death but had not been brought to justice over the murder for fear this might jeopardise the Northern Ireland peace process.
- The Murder of Jill Dando is on BBC One at 9pm, Tuesday April 2.
