The state failed to protect high-profile solicitor Rosemary Nelson before her 1999 murder by loyalists in the North, but did not collude in her killing, a major public inquiry has found.
However, the inquiry concluded that a rogue RUC officer or soldier may have helped the murderers to target her.
The inquiry believes intelligence was leaked outside the RUC and endangered Mrs Nelson's life.
The hard-hitting report found no evidence of a direct role in the car bomb attack 12 years ago, but it said it could not rule out the possibility of involvement by a rogue element of the security forces
The inquiry, which cost £46.5m, concluded that RUC officers publicly abused and assaulted the solicitor, and it believed police intelligence on the 40-year-old mother of three had leaked out.
Before her death on March 15, 1999, the lawyer, who worked on a number of controversial cases including those of suspected republican terrorists, had alleged police intimidation.
Those claims gained international attention and the report found police had made “abusive and threatening remarks” about the solicitor.
The public inquiry found that the state “failed to take reasonable and proportionate steps to safeguard the life of Rosemary Nelson”.
Current chief constable of the PSNI Matt Baggott apologised for police failings.
“The inquiry has produced a lengthy and critical report which I respect, and that we now need to study carefully,” he said.
“It has found that Rosemary Nelson was not given the attention, impartial treatment or protection that was her right and the responsibility of policing to provide.
“Where there are inadequacies and failings identified, I apologise to her family and friends, and on behalf of the police service, I am sorry.”
Secretary of State Owen Paterson presented the report to the House of Commons and noted its finding that there was "no evidence of any act by or within any of the state agencies...which directly facilitated" the killing.
Mr Paterson said: “I am profoundly sorry that omissions by the state rendered Rosemary Nelson more at risk and more vulnerable. It is also deeply regrettable that despite a very thorough police investigation no-one has been charged for this terrible crime.”
But the Labour Party at Westminster, as well as the SDLP and Sinn Féin in Belfast, accused Mr Paterson of playing down the more serious aspects of the report findings.
The 700 word report included two and a half pages of conclusions which list its key findings.
In said it believed that RUC intelligence on Mrs Nelson had leaked out and, whether the information was correct or not, it had “increased the danger to Rosemary Nelson’s life”.
The report authors also believed the claims made by Mrs Nelson before her death, that policemen had threatened her during interviews with her clients. They added: “This became publicly known and would have had the subsequent effect of legitimising her as a target in the eyes of loyalist terrorists.”
The report also concluded:
:: Mrs Nelson’s involvement in high profile cases involving nationalist and republican clients made her “an obvious trophy target”.
:: RUC management “failed to intervene” to prevent officers “uttering abuse and threats to defence solicitors, including Mrs Nelson”.
:: The RUC failed to pay attention to Mrs Nelson’s home and office addresses as promised.
:: There was a “corporate failure by the RUC” to warn Mrs Nelson of her vulnerability
:: The Northern Ireland Office did not press the police on Mrs Nelson’s case.
The report said: “The combined effect of these omissions by the RUC and the NIO was that the state failed to take responsible and proportionate steps to safeguard the life of Rosemary Nelson.”