North Wales Police "could and should" have done more to protect a domestic abuse victim who was murdered by her ex-partner, a report has concluded.
An investigation by the Independent Police Complaints Commission (IPCC) was carried out after Karen McGraw, 50, was murdered at her Flintshire home by Trevor Ferguson.
But the IPCC found the force could not have prevented the "heinous crime".
The force said it was "sorry" for not providing her support and protection.
Ferguson, from Greater Manchester, was jailed for life and must serve a minimum of 17 years after being found guilty of murder in December 2009.
The trial heard the 49-year-old entered her home in Connah's Quay and stabbed her three times "simply because she refused to take you back into her home".
The jury had been told that Ferguson had previously assaulted Ms McGraw, and she had contacted police.
That led to an investigation by the IPCC which examined the force's response to reports of domestic abuse made by her between April and July last year.
The IPCC said its investigation found the relationship between Ms McGraw and Ferguson was "complex",
But it found the force "failed on a number of occasions" to properly risk assess and deal with her "escalating anxieties and the increasing risk" she faced.
It also stated: "The IPCC is clear that the areas where North Wales Police did not properly follow force policy and best practice in dealing with domestic abuse did not make the force responsible for her murder by Ferguson."
IPCC Commissioner for Wales, Tom Davies, said: "Karen McGraw was brutally murdered and her family has every justification in wanting to know whether more could have been done to help her.
"Our investigation has shown that more could and should have been done to provide Karen with the support and protection she needed.
"This does not mean that her murder could have been prevented and Ferguson alone is responsible for this heinous crime."
He added: "Domestic abuse is a very challenging crime for the police service to deal with.
"The experts agree that it is essential that officers take proper notes and keep full records.
"This helps in accurate risk assessments and in ensuring that any follow-up action is taken.
"The police service periodically runs anti-domestic abuse campaigns which are essential in raising the confidence of women to report incidents to the police.
"What is equally important is that the police service maintains the impetus of those campaigns so that officers and staff continue to be provided with training, refresher training and reminders of force policies."
Following the trial, sentencing judge, John Rogers QC, commended the actions of Flintshire council, North Wales Police and agencies who support abused women for their prompt response.
North Wales Police's Deputy Chief Constable Ian Shannon said: "Karen McGraw was brutally murdered and our thoughts are with her family who are quite rightly seeking to fully understand what happened in the time leading up to this tragic incident.
"We welcome the IPCC's report and we are sorry that we were not able to offer Karen all the support and protection she needed."
He added said the force had improved the way officers respond to domestic abuse and many of the IPCC's recommendations were in place.
He said: "We will continue to revise the way in which we record and share information in such cases and we are developing enhanced training packages for officers and staff to enable them to quickly and clearly identify any risks."
Mr Shannon said the force took all issues relating to domestic abuse "seriously" and was working with agencies to prevent and reduce domestic abuse.
"We are committed to protecting anyone who becomes a victim of such abuse and to bringing offenders to justice," he added.