Swedish prosecutors have named the man who they say killed former Swedish prime minister Olof Palme in 1986, ending years of mystery.

They identified the suspect as Stig Engstrom, also known as "Skandia Man", who killed himself in 2000.

As a result they are closing the investigation into Palme's death, Chief Prosecutor Krister Petersson said.

Palme was shot in the back as he walked home from the cinema with his wife Lisbet in Stockholm.

He had dismissed his security team earlier in the day. The assassination took place on Sweden's busiest road and more than a dozen witnesses saw a man fire the shots before fleeing the scene.

Thousands of people have been interviewed over his death. A petty criminal was convicted of the killing but the verdict was later dismissed.

What did the prosecutor say?

"The person is Stig Engstrom," Mr Petersson told a news conference. "Because the person is dead, I cannot bring charges against him and have decided to close the investigation."

"How he acted was how we believe the murderer would have acted," he added.

Mr Petersson said Stig Engstrom had not initially been a focus for the investigation, but when investigators looked into his background they found he was accustomed to using weapons, having been in the army, and was a member of a shooting club.

In his local area he was also part of a circle of critics of Palme's policies and relatives said he had a negative view of the prime minister.

Engstrom had long running financial problems and a growing problem with alcohol, Mr Petersson said.

Who was Stig Engstrom?

Stig Engstrom became known as Skandia Man as he had worked for the Skandia insurance company. He had been working late on the evening of the murder at the the firm's HQ close to the crime scene.

Engstrom, who was one of some 20 people who witnessed the assassination, eventually killed himself in 2000.

He was first identified as a suspect by journalist Thomas Pettersson, and police started looking into Engstrom 18 years after his death. It was suggested Engstrom had killed Palme because of the prime minister's left-wing views.

He lied about the moments after the murder, even claiming he had tried to resuscitate Palme. It later emerged he had had weapons training.

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Stig Engstrom's ex-wife told Expressen newspaper in 2018 that she had been questioned by detectives in 2017. At the time she said the suspicion of his guilt was out of the question.

"He was too much of a coward. He wouldn't harm a fly," she said.

How was Olof Palme murdered?

The Swedish prime minister had discharged his guards on a Friday night on 28 February 1986 and had gone to the cinema with his wife Lisbet, their son Marten and his girlfriend.

Walking with his wife after the film on Stockholm's busiest street, Sveavagen, they were attacked by a gunman from behind.

Palme, 59, was shot in the back and died instantly. Bullets were recovered at the scene from a .357 Magnum handgun, but the gun was never found.

Why was no-one caught?

One man did go to jail. Convicted criminal Christer Pettersson - who has no connection to the prosecutor - was identified in a line-up by Lisbet Palme and jailed for life in 1989.

But he was quickly released on appeal as no motive had been established and no weapon retrieved. Pettersson died in 2004.

Who were Palme's enemies?

A charismatic prime minister who led Sweden's Social Democratic party, Plame was also outspoken on several international issues.

At home he had infuriated business owners with reforms and spoken out against nuclear power.

He was critical of the Soviet invasion of Czechoslovakia in 1968 and the US bombing of North Vietnam and had attacked South Africa's "gruesome" regime of apartheid.

What theories have there been?

The case has dogged Swedish police for decades. For years it obsessed renowned author Stieg Larsson, who wrote The Girl with the Dragon Tattoo.

Among the theories put forward over the years, Palme was assassinated because:

• He stood up against apartheid and funded the African National Congress (ANC) - Swedish police travelled to South Africa in 1996 to investigate the claim
• Palme had discovered that Swedish arms firm Bofors had used bribery to set up an Indian weapons deal
• Palme's government had declared the Kurdish militant PKK group terrorists

Lisbet Palme died in 2018 without knowing conclusively who murdered her husband.

BBC