Police are continuing to question the 66-year-old former British paratrooper over the deaths of three people on Bloody Sunday, in Derry, in January 1972.
In total 14 people died on Bloody Sunday when British paratroopers opened fire on a civil rights march.
On Tuesday the former paratrooper was arrested in Antrim with relation to the deaths of William Nash (19), Michael McDaid (20) and John Young (17). The 66-year-old man was known as “Lance Corporal J” when he gave evidence as part of the Saville Inquiry into the attack.
The suspect is currently being detained by the Police Service of Northern Ireland’s (PSNI) Legacy Investigations.
The retired soldier is being questioned by detectives on suspicion of murdering all three men. All of whom were shot dead in close proximity to one another at a rubble barricade on Rossville Street. The Irish News reports that he is also being questioned with relation to the attempted murder of William Nash's father Alexander. Nash came to the barrier to save his son but was shot in the arm and body.
Speaking to press members of the families of those killed said their looked forward to a prosecution for the crimes committed on Bloody Sunday soon. However former Northern Ireland secretary Lord Peter Mandelson told Channel 4 news "there are perils in going back so far into history."
"Perils over the evidence that is available, people's memories, people's ability to produce their own evidence and facts so long ago to present to some sort of tribunal or commission or court of law or whatever it is,” Mandelson added.
"I think there's a broader point to which is that peace in Northern Ireland is quite fragile, community relations are fragile and we have to think very hard before we do anything that is going to make the fragile worse, which is going to fire up tensions between different parts of the community," he said.
"I'm sure that a lot of thought has been put into this and I'm not going to second guess those who have made this decision, but I do hope that before further decisions of this kind are taken, people think long and hard about the perhaps unforeseen consequences of going so far back into the past."
John Young was just 17 when he was killed on Bloody Sunday. His brother spoke to BBC Radio Foyle and said he welcomed the news.
"A prosecution has to happen soon. We waited for over 40 years and this is a big step,” said Young.
"I think about my brother every day. His life was cut short and I keep thinking about him because he would probably be married today.
Similar, John Kelly, whose brother Michael was among those killed, said this news brings fresh hope.
Kelly said “My brother's death is no different to any other death on that day. This is major development and I hope there is an arrest in relation to my brother soon.
Bloody Sunday - An act of mass murder by the British army in Derry. pic.twitter.com/dYqhuTyStJ— Short Strand (@Short_Strand) November 10, 2015
"Hopefully there will be prosecutions soon."
Sir Gerald Howarth, a Conservative British member of parliament and former defense minister, represents former soldiers on duty at the time of Bloody Sunday. He told the BBC that these families are not unique.
"We cannot forget that a lot of families haven't had justice yet," said Sir Howarth.
"It would be good if we could just close this chapter.
"I'm not excusing what happened but I do not think it is in the public interest for former soldiers to be prosecuted.
"This is now a matter for the prosecuting authorities though."
Gregory Campbell, member of parliament for the Democratic Unionist Party, for East Derry, also questioned if all killings around the time of Bloody Sunday would be investigated.
He said "It remains to be seen whether the current investigations will focus solely on the actions of soldiers on that day or whether progress will be made on arresting others who were engaged in illegal terrorist activity at the same time.
"Two police officers were in a patrol car on part of the route of the march three days before Bloody Sunday and were murdered by the Provisional IRA.
"The police need to confirm if they are questioning anyone in relation to that double murder or the other murders that occurred around the same time.
"Are they following any lines of inquiry against individuals who were not police or army personnel serving in Londonderry at that time?"
The PSNI launched a murder investigation into the events in 2012 following the finding of the Saville Inquiry, which found that none of the victims was posing a threat to soldiers when they were shot.
Following the publication of this report, in 2010, British Prime Minister David Cameron apologized for the army's actions, branding them "unjustified and unjustifiable."
The British government said it would not comment on an individual case. However a spokesperson released the following statement:
"So far as our overall approach to these matters is concerned, the government believes in the rule of law. Where there is evidence of wrongdoing it is right that this should be investigated and, where the evidence exists, for prosecutions to follow.
"We remain unstinting in our admiration and support for the men and women of the police and armed forces whose sacrifice ensured that terrorism would never succeed in Northern Ireland, and that its future would only ever be determined by democracy and consent.
"The overwhelming majority carried out their duties with courage, professionalism and integrity. This government will never forget the debt of gratitude we owe them."