Libyan man arrested over 1984 murder of policewoman Yvonne Fletcher
A man has been arrested on suspicion of conspiring to murder Pc Yvonne Fletcher, who was shot dead outside the Libyan embassy in London 31 years ago.
The Libyan suspect, in his 50s,was held at a location in south east England in what police described as "the first significant arrest" of the investigation into the 25-year-old officer's killing in 1984.
Detectives have also arrested a man and a woman on suspicion of money laundering.
Commander Richard Walton, the head of the Met's counter terrorism command, said the trio were arrested on Thursday morning.
The man arrested on suspicion of conspiracy to murder was also held on suspicion of money laundering.
The second man and the woman detained on suspicion of money laundering, who are aged in their 30s and 40s respectively, are also Libyans. They were arrested at separate addresses in London and south east England.
All three remain in custody and searches are under way across the country.
Mr Walton said: "Over the past 31 years we have never lost our resolve to solve this case, to bring to justice those who conspired to commit this act of murder."
Wpc Fletcher, who was unarmed, suffered a fatal shot to the back as she policed a demonstration against Colonel Muammar Gaddafi outside the Libyan People's Bureau in St James's Square on the morning of April 17, 1984.
Mr Walton said that at about 10.17am a number of shots were fired from within the bureau, hitting the officer.
He told media at Scotland Yard: "I can tell you today the we believe two firearms were used- a pistol and and an automatic weapon."
Ten Libyan men protesting against Gaddafi were also shot and injured.
The demise of Gaddafi, who died in 2011 during civil war in Libya, and the regime change has "provided access to new lines of inquiry and displaced many people outside of Libya", Mr Walton said.
Announcing the arrests, Mr Walton also said police were offering a reward of up to £50,000 for information leading to the arrest and prosecution of those responsible for the murder.
Police are also launching an international Facebook campaign for information.
Wpc Fletcher's family made an emotional appeal for help in securing justice over her death.
"It is now 31 years since Yvonne was shot and killed outside the Libyan People's Bureau in St James's Square," they said.
"Recently we have had to come to terms with another loss through the death of Yvonne's father, Tim.
"His one regret in life was that no one had been arrested in connection with the murder of his daughter and he never witnessed any justice.
"Resolving this crime is still important to all the family.
"Any information, however small, can help bring closure for the family and we therefore continue to support the Metropolitan Police in their ongoing investigation.
"This is a difficult time for us and we will be making no further comment at this present time."
UK Prime Minister David Cameron's official spokeswoman said: "It would be inappropriate for us to comment on an ongoing case.
"But it does remind us all of the dangers that our brave police officers face on a daily basis and the extraordinary courage they show.
"And it highlights the determination of the police to pursue those who attack others and make sure people are brought to justice."
Scotland Yard has also released 14 images of individuals from the pro-Gaddafi group who they want to trace, as well as video footage of the demonstration and shooting.
The 54-second clip shows the chaotic moments after the shots were fired.
Dozens of demonstrators gathered behind a metal cordon in the square fall to the ground after a loud bang is heard, dropping placards and collapsing on top of each other.
Uniformed officers pour into the picture as they attempt to ascertain what has taken place, before Wpc Fletcher is seen stricken on the ground yards from the protesters.
She is quickly surrounded by stunned colleagues, including one who throws his police helmet to the ground as he attempts to tend to her.
Speaking at a press conference in Nicosia, Cyprus, Foreign Secretary Philip Hammond said: "We have supported over many, many years the continued investigation into the murder of Wpc Yvonne Fletcher.
"Obviously that has been difficult for much of that period because of the situation in Libya.
"I am delighted that the investigation has made progress."