A 66-year-old former British soldier was arrested Tuesday in County Antrim in Northern Ireland over the 1972 shooting deaths of 14 unarmed Irish protesters, in an event that came to be known as "Bloody Sunday." The massacre of the protesters sparked several decades of violent uprising in the region, an era referred to as The Troubles in Northern Ireland.

Civil rights protestors were marching through the streets of Londonderry in Northern Ireland Jan. 30 1972 when their path was blocked by British soldiers. Scuffles began to break out between the unarmed protesters and the soldiers, leading the soldiers to open fire on the crowd, killing 14 and wounding many more.

The deaths of the Irish protesters started a more than 30-year violent conflict in the region between Loyalists, who pledged allegiance to the British crown and wanted to remain under U.K. rule and Republicans, who sought to join the rest of the Republic of Ireland. The Loyalists were predominantly Protestant and the Republicans predominantly Catholic.

An investigation into the events of "Bloody Sunday" has been ongoing in the more than 40 years since, sparking anger among many people in Northern Ireland after no arrests were made for nearly a half-century. Prime Minister David Cameron apologized in 2010 on behalf of the state for the deaths of the protesters.

The arrest "marked a new phase in the overall investigation which would continue for some time," said Detective Chief Inspector Ian Harrison, the leading authority on the case, as reported by the BBC. The following Tweet was posted from the verified account of the Police Service of North Ireland Tuesday.

The name of the former British soldier accused of the killings has not yet been released. More than one soldier opened fire on the protesters, according to eyewitness reports and video footage available. No other arrests have yet been announced.