On Sunday, January 30, 1972, during a civil-rights march in Derry, Northern Ireland, British paratroopers opened fire on unarmed demonstrators and 22-year-old James Wray was hit in the back trying to escape the melee. As he lay on the ground, unable to move, the paratroopers closed in, still firing. Residents called out to Wray to pretend he was dead. Then they saw his jacket jump as another bullet entered his back. He lay motionless. He was dead.

For almost half a century, the British government avoided calls to bring criminal charges against paratroopers who shot and killed 14 unarmed Catholics on what became known as Bloody Sunday. Then, last week, the government announced that one of paratroopers, identified only as Soldier F, would be charged with two murders, one of them of Wray, and the attempted murders of four others. The other paratroopers who fired shots that day will not be prosecuted for lack of evidence “sufficient to provide a reasonable chance of conviction.”

To put it mildly, the relatives of the other 12 killed are disappointed. The relatives of 17-year-old Michael Kelly are shocked because Soldier F admitted shooting him and the bullet that lodged in his spine was shown to have been fired from Soldier F’s rifle, but he is not being prosecuted for that crime.

The relatives are ready to mount court challenges, but they will have to overcome a string of adroit legal maneuvers—“modifications of position” is one political term that comes to mind—that the British government has employed over the years to make the inconvenient truth fade away, and put prosecutions out of reach.

How did the government think this might happen in the case of Bloody Sunday, a pivotal point in the Troubles, that deepened and prolonged the bloody conflict?

There has been no lack of evidence. A public inquiry, convened a month after the killings largely exonerated the soldiers, but was shown to be a whitewash. In 1974, a coroner’s report concluded that the paratroopers had “run amok,” prompting relatives to press for another investigation.

A quarter of a century later, Lord Saville oversaw the longest—at 12 years—and the most expensive—at 200 million pounds—public inquiry in British history. Two thousand witnesses gave statements, including paratroopers who were identified only by letters. Saville concluded that none of the victims was armed, that the soldiers had “lost control” and fired without warning. Saville also found that some of the soldiers had lied. One of those was Solider F, now accused of murder.

The Saville report prompted then–Prime Minister David Cameron to issue an apology on behalf of the government and to describe the killings as “unjustified and unjustifiable.” This, in turn, prompted a criminal investigation by the Northern Ireland police, which ended in last week’s murder charges.

Some relatives felt their efforts to find the truth had been at least partly vindicated. One of them was the wife of Barney McGuigan, aged 41, the oldest person killed on the march and father of six children, who, according to the Saville report, had been shot by Soldier F. Bridie McGuigan did not want to pursue prosecutions. “What is the point?” she asked. “What is the point of him going to jail. Would it take away my pain? No, it wouldn’t and we, as a family, do not want Soldier F’s family to go through what we went through.”

Last week, as the government prosecutor announced that none of the evidence in Saville could be used in criminal proceedings against Soldier F, or any of the other paratroopers, any residual goodwill built up over the years of official inquiries seemed in danger of being swept away.

Potentially corroborating evidence in McGuigan’s case is also now unavailable. Soldier G, Soldier F’s comrade in arms, has died. McGuigan was shot in the back of the head, and his face blown away as the bullet splintered into 40 pieces, leaving no possibility of tracing it back to a soldier’s high-powered assault rifle. The defense ministry has either sold or destroyed the rifles used on that day.

Bridie McGuigan has since died, but the lawyer for her estate, Des Doherty, told me he is “carefully reflecting” on the prosecutor’s decision and nothing is ruled out with regard to future legal actions.

If the relatives of the victims are successful in bringing other prosecutions, it would be a remarkable victory for justice against a government that evidently hoped the problem would go away by paying off the relatives two years after the event. In 1974, the government awarded the victims’ families payments “in a spirit of goodwill and conciliation.” Relatives of four teenagers who were killed received pounds sterling 250 each. James Wray was given pounds one thousand, five hundred. Bridie McGuigan, mother of six, received a check for pounds sterling 3,750.