Four men accused of taking part in the 1994 Rwandan genocide have been freed by a British court after their lawyers said they would not face a fair trial if they were extradited to Africa.
Their release coincided with commemorations in Rwanda to mark the 15th anniversary of the atrocity, which began on 6 April.
Judges in the High Court in London ruled there was "a real risk [the men] would suffer a flagrant denial of justice" if returned to Rwanda for trial. Under UK law, genocide and war crime offences commited before 2001 cannot be prosecuted here.
Vincent Bajinya, who had changed his name to Brown, Celestin Ugirashebuja, Emmanuel Nteziryayo and Charles Munyaneza were arrested in London, Essex, Manchester and Bedford and had been held in custody since December 2006 under a memorandum of understanding in which Rwanda waived the death penalty.
All four are accused of killing, or conspiring with or aiding and abetting others to kill, members of the Tutsi ethnic group "with the intent to destroy in whole, or in part, that group".
Lord Justice Laws and Lord Justice Sullivan allowed their appeals against the Home Secretary Jacqui Smith's extradition orders. The judges said there was evidence that defence witnesses were afraid to give evidence.
The judges declared: "We conclude that if [the four] were extradited to face trial in the High Court of Rwanda, the appellants would suffer a real risk of a flagrant denial of justice by reason of their likely inability to adduce the evidence of supporting witnesses."
The judges also ruled there was a real risk" of [government] interference with the judiciary" in Rwanda.
They refused the Rwandan Government, represented by the Crown Prosecution Service (CPS), leave to appeal to the House of Lords against the ruling. A spokeswoman for the CPS said the ruling ended the extradition process.
All four cases had been considered by the International Criminal Tribunal for Rwanda, based in Tanzania, but the files were given to the Rwandan Government for further investigation in 2005.
Lord Gifford QC, who appeared for Munyaneza, said the case had revealed "an emerging international consensus that there is no fair trial in Rwanda".
Frank Brazell, a solicitor for Vincent Brown, welcomed the decision: "We are hugely pleased with the result. The central issue they have found is that there is clearly no prospect of these men having a fair trial in Rwanda."
He said Mr Brown, a British national and qualified doctor who had worked for a charity training nurses, would be released from custody immediately.Mr Brazell said the issue of compensation would be discussed in due course.
People suspected of genocide, war crimes and crimes against humanity can only be prosecuted in the UK if the acts were committed overseas after 2001, when the International Criminal Court Act was enacted.
The Aegis Trust, which is responsible for the Kigali Genocide Memorial Centre in Rwanda, where 250,000 victims are buried, has been lobbying MPs and Lords to amend the UK law.
Dr James Smith, the chief executive of the trust, said: "For survivors, this verdict couldn't come at a worse time. It destroys hope. It demonstrates that the suspected killers of their families enjoy freedom in Europe. The impunity of genocide suspects is a denial of justice for the survivors.
"If British courts cannot extradite these men to Rwanda, the British Government should immediately amend UK law to enable the prosecution of suspected mass murderers."
A CPS spokesman said: "Although the High Court upheld the District Judge's findings that there was evidentially a prima facie case against each defendant, the finding in relation to the real risk of a flagrant violation meant their extradition could not continue."