It comes after the law enforcement watchdog published findings of an inquiry into the murders of RUC constables Harold Beckett and Gary Meyer on June 30 1990 and October 4 1989 respectively.
Marie Anderson’s office probed two referrals from the Police Service of Northern Ireland and two public complaints which date back to 2015.
The killings were referred to the Ombudsman by Chief Constable Jon Boutcher as well as family members of the deceased.
They centred around statements made by two men that the Weapons and Explosives Research Centre (WERC), part of RUC Special Branch, tested and then returned live weapons to the control of paramilitaries.
One statement was made by a former police officer attached to the WERC and reported as part of a television documentary.
The other statements were made by a civilian member of WERC staff to the Stevens Inquiry.
Both men alleged that operational guns returned to paramilitaries were subsequently used in the murders of police officers Harold Beckett and Gary Meyer on June 30 1990.
The ombudsman investigation also considered a complaint from Constable Beckett’s daughter about the RUC investigation into her father’s death, and the family of James Henry Babington, who was shot dead on October 4 1989.
His murder was linked ballistically to the murders of the two constables.
Mrs Anderson said her investigation established that the weapons referred to in the statements by the former police officer and former WERC employee were not those used in the murders of Constable Beckett and Constable Meyer.
The Ombudsman said that it had been “unable to conclude definitively” on the allegations that weapons returned to paramilitaries during operations were used to conduct the murders of the RUC Mr Beckett and Mr Meyer.
Police Ombudsman Mrs Marie Anderson, said: “My investigation has established that the weapons referred to in the statements by the former police officer and former WERC employee were not those used in the murders of Constable Beckett and Constable Meyer.
Deputy Chief Constable Bobby Singleton issued an apology on behalf of the PSNI (Niall Carson/PA)
News Catch Up – Wednesday 3 December
“However, in light of the available evidence and intelligence, it has not been possible to conclude definitively on whether WERC had any involvement in the weapons which were used in their murders.”
Speaking after the findings, Deputy Chief Constable Bobby Singleton apologised to the families of both constables on “yet another difficult day”.
“Our first thoughts today are with the families of Constable Harold Beckett, Constable Gary Meyer and James Henry Babington who have had to live with the devastating loss of their loved ones by terrorists for many years,” the Deputy Chief Constable. “Today will have been yet another difficult day.
“I want to publicly apologise to the Beckett, Meyer and Babington families on behalf of the Police Service of Northern Ireland for the failings which have been highlighted in the handling of this case, the events prior to their murders and the subsequent investigation.”