LONDON -- Police in Northern Ireland on Tuesday arrested a 66-year-old former soldier in the 1972 Bloody Sunday killings - the first such detention since the start of a murder investigation three years ago.
The Police Service of Northern Ireland began the probe in 2012 after a government inquiry found that none of the 13 Irish demonstrators killed was posing a threat to soldiers when they were shot.
Britain's Ministry of Defense confirmed that the man arrested Tuesday in County Antrim had been a soldier. It didn't provide details, saying it wouldn't be appropriate because criminal investigations are ongoing.
Detective Chief Inspector Ian Harrison, who leads the investigation, said the arrest marked a "new phase in the overall investigation," which would continue for some time.
Thirteen people were shot dead on Jan. 30, 1972 in Londonderry when British paratroopers opened fire on a civil rights protest. A 14th person later died.
Britain admitted that its troops were fully at fault following a long-running inquiry chaired by English Judge Mark Saville in 2010. Following the publication of the report, Prime Minister David Cameron apologized to the victims, branding the army's actions as "unjustified and unjustifiable."
Police in Northern Ireland announced in September that they would interview former soldiers about their involvement.