LONDON (AFP) - British police arrested a former soldier on Tuesday (Nov 10) on suspicion of murdering three people on Bloody Sunday in 1972, one of the most notorious incidents of Northern Ireland's troubled past.
It was the first arrest since a murder investigation was opened in 2012 into the killings of 13 Catholic civil rights protesters on the streets of Londonderry that day, and another victim who died months later of his injuries.
A police source said the man, an ex-soldier, was being questioned by detectives investigating the murders of William Nash, 19, John Young, 17, and Michael McDaid, 20, who were shot and killed at a rubble barricade.
"Detectives from Legacy Investigation Branch investigating the events of Bloody Sunday have arrested a 66-year-old man in County Antrim," police in Northern Ireland said in a statement.
They added that the arrest marked "a new phase in the overall investigation which would continue for some time".
The Defence Ministry said it was "aware an ex-soldier has been arrested".
Political party Sinn Fein, formerly the political wing of the Irish Republican Army (IRA) paramilitary group, welcomed the arrest of the man, whose identity has not been released.
Bloody Sunday helped bolster support for the IRA during 30 years of unrest in Northern Ireland, a period known as The Troubles, in which around 3,500 people died.
"This is another step forward in the long campaign for justice by the Bloody Sunday families," said Mr Raymond McCartney, a Sinn Fein politician and former member of the IRA.
The IRA waged a campaign of violence to drive Britain out of Northern Ireland until the unrest largely ended with a 1998 peace deal. But sporadic bomb and other attacks have continued, which police have blamed on paramilitary groups.
An initial investigation into Bloody Sunday published in 1972 took only a month to report and largely exonerated the British army, leading to accusations of a whitewash.
Families of the victims had long campaigned for a review, and in 2010 a 12-year inquiry by London concluded that none of the victims posed a threat and that the soldiers gave no warning before firing.
Prime Minister David Cameron apologised on behalf of the British people, describing the army's actions as "unjustified and unjustifiable".
Ms Kate Nash, sister of Bloody Sunday victim William Nash, called the arrest "a positive step", adding: "We have always fought very hard to be treated equally within the justice system."
British media reports said the man arrested was also being questioned over the attempted murder of Mr Nash's father Alexander, who was shot in the arm and body while trying to save his son.
The British inquiry said it was possible that one of two soldiers could have shot Alexander, but there was insufficient evidence to be sure.
The 2010 probe also claimed that soldiers put forward false accounts of the incidents to justify their firing.