BELFAST, July 2 (Reuters) - The only British soldier charged with murder over the "Bloody Sunday" killings of 13 unarmed Catholic civil rights marchers in Northern Ireland in 1972 will not face trial, prosecutors said on Friday. The decision angered victims" families, who said they would seek a judicial review, underlining the bitterness still felt nearly 50 years after the worst single shooting incident of “The Troubles” -- three decades of sectarian violence involving Irish nationalists seeking a united Ireland and pro-British forces. "It"s a day of devastation but we"re not going to give up. The fight for justice goes on," John Kelly, whose brother Michael was among those killed, told a news conference. Soldiers from the Parachute Regiment opened fire on an unauthorised march in the city of Londonderry, an Irish nationalist area, killing 13 people and wounding 14 others, one of whom died later. The unnamed soldier, dubbed "Soldier F", was charged in 2019 with the murders of two men and attempted murders of five others. The evidence was insufficient to charge 16 other former soldiers. The Public Prosecution Service (PPS) said it decided not to proceed after considering the impact of a recent court ruling that evidence relied upon in the prosecution of two former soldiers in a separate 1972 killing was inadmissible because of how it was obtained. There was no longer a reasonable prospect of key evidence being ruled admissible and without this the test for prosecution was no longer considered met, prosecutors said. "I recognise these decisions bring further pain to victims and bereaved families who have relentlessly sought justice for almost 50 years and have faced many set-backs," Director of Public Prosecutions Stephen Herron said in a statement. Proceedings against another soldier who was to be prosecuted with the murder of a 15-year-old boy in July 1972 were also dropped on Friday. A judicial inquiry into the events of Bloody Sunday, which took place at the height of Northern Ireland"s 30-year conflict, said in 2010 the victims were innocent and had posed no threat to the military. The conflict pitted mostly Catholic nationalists fighting for a united Ireland and mostly Protestant unionists, or loyalists, who wanted Northern Ireland to stay part of the United Kingdom. The British army, originally sent into the province to keep the two sides apart, largely combated the IRA (Irish Republican Army). The 1998 Belfast or Good Friday Agreement ended most of the violence. The British government announced in May that it would introduce legislation to give greater protection to former soldiers who served in Northern Ireland and face potential prosecution, plans Dublin and many in Belfast fiercely oppose. read more