LONDON — Authorities in the United Kingdom on Friday halted the prosecution of two former British soldiers over the killing of three people almost 50 years ago in Northern Ireland, including two who died on Bloody Sunday — one of the deadliest days in the conflict known as The Troubles.

The decision to discontinue proceedings against the two men, known only as Soldier F and Soldier B, came after a judge recently threw out evidence against two other former soldiers because of the way it was obtained. As the cases were similar, prosecutors concluded there was no reasonable prospect of a conviction in the cases against Soldier F and Soldier B.

Director of Public Prosecutions Stephen Herron said prosecutors had a duty to review the cases in light of the new information, despite the “extreme distress” caused by their decision.

“I recognize these decisions bring further pain to victims and bereaved families who have relentlessly sought justice for almost 50 years and have faced many setbacks,” Herron said. “It is clear to see how these devastating events in 1972, in which the families involved lost an innocent loved one, caused an enduring pain which continues to weigh heavily.”

The victims’ families have spent years campaigning for justice for those killed and injured on Bloody Sunday, while supporters of British veterans argue that aging former soldiers shouldn’t be prosecuted for making split-second decisions decades ago.

Family members were bitterly disappointed by Friday’s decision and said they planned to challenge it.

“You can get away with the murder of a child if you are in the British Army because the state will always protect you,” Des Doherty, the lawyer for one of the families, said after meeting with prosecutors. “The state will subvert the legal system and use it to their advantage. And they’ve done so in the past. And then the illegitimate will be legitimized by the (Public Prosecution Service) and the courts.’’

The decision means Soldier F won’t be tried for the killings of James Wray and William McKinney and the attempted killings of Joseph Friel, Michael Quinn, Joe Mahon and Patrick O’Donnell in Londonderry, also known as Derry, on Bloody Sunday, Jan. 30, 1972.

In a separate case, the veteran identified as Soldier B won’t face prosecution for the killing of 15-year-old Daniel Hegarty on July 31, 1972, in the same community.

The shooting occurred during Operation Motorman, an Army drive to wrest control of no-go areas from the Irish Republican Army. Daniel and his 16-year-old cousin, Christopher, who had gone to watch the military operation, were shot after encountering an Army patrol.

Prosecutors began pursuing the cases after the conclusion of the Bloody Sunday Inquiry in 2010, which was designed to find out what happened, not bring criminal charges.

The inquiry found that British soldiers had opened fire without justification at unarmed, fleeing civilians and then lied about it for decades. Those findings refuted an initial investigation that took place soon after the slayings, which branded the demonstrators as IRA bombers and gunmen.

Herron stressed that Friday’s decision doesn’t change the fact that “those killed and injured in these tragic incidents were entirely innocent.”

Bloody Sunday has come to symbolize The Troubles in Northern Ireland, the long-running conflict between mainly Catholic supporters of a united Ireland and predominantly Protestant forces that want to remain part of the United Kingdom. Tensions have eased since the 1998 Good Friday peace accord, which created a system for Republican and Unionist parties to share power in Northern Ireland.

But the aftermath of the conflict still lingers for the survivors and the soldiers who were dispatched to Northern Ireland during the violence.

Johnny Mercer, a Conservative Party lawmaker, has sought legislation to prevent Northern Ireland veterans from facing repeated investigations for alleged crimes that took place decades ago in the heat of battle. He resigned from Prime Minister Boris Johnson’s Cabinet after the government failed to back his proposal.

“Another terribly sad day for Northern Ireland,” Mercer said on Twitter. “Both for families who have been dragged along an unachievable path, and for veterans who’ve been broken by the process.”