A police force has apologised for systematic failings which contributed to the brutal murders of a woman and her two-year-old daughter.
David Oakes, 50, shot dead his ex-partner Christine Chambers, 38, and their daughter Shania at their home in Braintree, Essex, in June last year.
Oakes is serving a whole life sentence after a court heard he "systematically tortured" Ms Chambers for several hours before the shotgun killings.
Ms Chambers' 10-year-old daughter fled the house during the ordeal as police outside attempted to negotiate with the killer.
The couple, who had a long history of domestic abuse, were due to appear at a court custody hearing the next day.
Today the Independent Police Complaints Commission (IPCC) published a report highlighting a catalogue of failings within Essex Police when investigating previous incidents involving the couple.
Incidents involving the couple reported to the force over a two-year period were treated in isolation by officers, with the force not taking Ms Chambers' fear of her partner into consideration as a motivation for her not pursuing complaints against Oakes, the report said.
An escalation in the number of calls from Ms Chambers in the two months before the murders was also missed by the force, the IPCC found.
Ms Chambers' father Ken welcomed the report and said he felt the force could have done more to prevent the deaths. However, he praised Essex Police for the way officers investigated the murders.
In a statement he said: "We realise one evil man is responsible for taking Christine and Shania away from us and not having them in our lives any more remains extremely difficult to bear.
"While we understand at times Christine could have been more co-operative with the police, we do feel that Essex Police could have done more to prevent the deaths.
They should have taken greater steps to protect Christine, for instance, we are still of the view she should have had a panic alarm installed at her home which may have allowed her to summon assistance at a crucial time after her phones had been smashed. And we think that officers dealing with ongoing incidents should have been more aware of the history and should have better identified the risks."
Mr Chambers added: "As a family we would again like to say thank you to all those, including friends and neighbours, who have shown us such support and kindness since the murders of Christine and Shania.
"We have also received marvellous support from the police murder investigation team led by Detective Chief Inspector (Godfrey) O'Toole, from police family liaison officers and the victim support service, and we are grateful to all of them for helping us through such a traumatic time."
The investigation said inadequate action was taken to arrest Oakes at the earliest opportunity when reports were made of him breaching a non-molestation order.
IPCC Commissioner Rachel Cerfontyne said: "The deaths of Christine and Shania Chambers are shocking to us all. It is impossible to say with any certainty whether if individual officers or the force had done things differently, Ms Chambers and Shania would still be alive today.
"While individual police officers could and should have done things better, this is not essentially a failure of individuals, but a failure of systems. The investigation identified a lack of adequate training, insufficient resources allocated to domestic violence cases and poor oversight.
"This is a tragic and disturbing case and the investigation has identified several key issues which apply to many other cases where domestic homicide is the outcome.
"Many women are reluctant to pursue criminal proceedings against abusive partners, sometimes even to seek help at all. There are many reasons for this, and often it is fear that they will exacerbate the situation and increase the danger they face.
"Undoubtedly this poses significant challenges for the police and other agencies, but it is essential in these situations that all possible is done to protect the victims and their children.
"Unwillingness to seek help or give evidence against the perpetrator is often due to fear and can be a sign of vulnerability, not culpability, and this must be recognised when a risk assessment is completed."
Assistant Chief Constable Maurice Mason offered "our deepest sympathies to the family and friends of Christine and Shania Chambers" on behalf of Essex Police.
He added: "Essex Police accepts the findings of the IPCC report, and apologises for the failures identified there.
"Every police officer involved in the case of Christine and Shania is devastated by their passing. I too am devastated by their deaths. I became a police officer to protect the vulnerable, and to put criminals like Oakes behind bars.
"Essex Police is committed to working tirelessly to reduce the likelihood of tragedies such as this from occurring again."
He added: "The unbelievable inhumanity of these murders led Oakes to be sentenced to two whole-life prison terms - the most extreme punishment which the British judicial system can impose.
"You would think that a man capable of such horror would have a history of violence. Oakes did not: he had no convictions or cautions for violence.
"In fact, the IPCC has found that significant 'information concerning Oakes's violence towards Christine Chambers was not available to the police or social services'.
"The IPCC also stated that there was no information that Oakes had access to a firearm. Essex Police acts promptly and decisively whenever it receives credible intelligence about illegally held weapons."
He said new procedures for sharing information between police forces and other organisations, such as social services, courts and solicitors, should be developed.