A police investigation into the murder of nationalist councillor Patsy Kelly in Co Tyrone in 1974 was "wholly inadequate", with the actions of RUC Special Branch indicative of "collusive behaviour", the Police Ombudsman for Northern Ireland has found.
Mr Kelly was last seen alive in the early hours of July 24, 1974, as he drove away from the Corner Bar in Trillick where he worked.
His body was found in Lough Eyes, near Lisbellaw in Co Fermanagh, three weeks later on August 10. He had been shot six times.
While loyalist paramilitaries claimed responsibility for the murder, the Kelly family believe the killing was perpetrated by members of an Army patrol.
No one has ever been charged or prosecuted over the murder.
Among findings published on Wednesday, Ombudsman Marie Anderson said the Kelly family was "failed by police".
Among the failings identified by the Police Ombudsman, she found that a senior investigating RUC officer showed "latent" investigative bias.
Marie Anderson concluded that the withholding of intelligence from the murder investigation team and the failure to act on intelligence about an active UVF unit in the Fermanagh area was indicative of "collusive behaviour" on the part of RUC Special Branch and the "L" Division Commander who was responsible for oversight of the investigation.
The Kelly family welcomed the ombudsman's report and said it vindicated their almost 50-year campaign for justice. They have called for a fresh inquest into the killing.
Police Ombudsman Marie Anderson said there was a series of "significant" investigative failings.
These included a failure to adequately verify the alibis of UDR members and failure to record detailed witness statements; a failure to link cases; and forensic failings including failure to make inquiries about footwear marks.
Officers also failed to recover a boat at Lough Eyes, with no record of fingerprint inquiries, and also failed to make inquiries about an anonymous letter, said the ombudsman.
She said there was a "latent" investigative bias on the part of the senior investigating officer.
"Investigative failings were central to the family's complaint and my investigation has found that there were a number of significant failings," said Mrs Anderson.
Patsy Kelly's widow Teresa and sons Patsy, Barry and Fearghal met with the Police Ombudsman in Belfast on Wednesday morning to receive the findings.
Afterwards, Patsy Kelly welcomed the report.
"Today is highly emotional for members of our family, a campaign of 50 years searching for truth and today we are vindicated in terms of the failings of police investigations," he said.
"We realise that today is a step forward in the overall campaign for truth and the next step in the process should be a fresh inquest that is granted immediately."
READ NEXT:
Campaigner urges stalking victims to contact police and use new law
Two firearms stolen in burglary while three children were at home
- Belfast landlord fined for 'gas safety breaches' in rented property
For all the latest news, visit the Belfast Live homepage here and sign up to our daily newsletter here.