POLICE and social services have come under fire for their investigations into a Bolton baby killer who murdered three generations of the same family.

Carl Mills' history in Bolton - in which there were 45 violent incidents - had not been properly researched, a report has revealed.

Kim Buckley, aged 46, her daughter Kayleigh, aged 17, and six-month-old granddaughter Kimberley were murdered in a house fire in Cwmbran, south Wales, in September 2012.

It was the first night prematurely born Kimberley had come home from hospital.

Kayleigh's boyfriend Mills was given a life sentence with a minimum of 35 years for their murder.

In the aftermath of his conviction, three reports were ordered - a serious case review (SCR), a domestic homicide review (DHR) and an investigation by the Independent Police Complaints Commission (IPCC).

All three reports have now been released and Gwent Police has been criticised for failing to find out about Mills' background.

The DHR review said information concerning Mills' history had not been "properly researched and considered", while the SCR highlighted 45 violent incidents during his time living in Bolton.

And the IPCC said Gwent Police did not properly identify Mills' "escalating behaviour" in the run up to the murders.

Officials said a police constable has since been given a written warning and sergeant given "management advice".

IPCC commissioner for Wales Jan Williams said: "To lose one member of your family is devastating, but for the surviving members of this family to cope with the loss of three is beyond comprehension.

"We will never be able to say whether their tragic deaths could have been prevented if different actions had been taken.

"However what is clear from our investigation is that the level of service provided by police to the family in response to their allegation of criminal damage fell well below the standard they should have expected."

Mills, a heavy drinker originally from Bolton, met Kayleigh via Facebook when she was 15 and he was 26.

His grooming of the teen prompted her worried mother to contact Gwent Police and social services - a move also followed by teachers and hospital staff.

Gwent Police carried out initial checks on Mills - but found "no trace" of previous convictions.

However, by December 2010 police discovered Mills had been to prison - and warned Mrs Buckley that he posed "a significant risk" to her daughter.

But to complicate matters, Kayleigh refused to co-operate with social services and when she turned 16 the report found she was seen as being responsible for her own choices.

In October 2011 she became pregnant with twins. Kayleigh miscarried one daughter in March 2012 and went on to have Kimberley, who was born 15 weeks early.

The little girl had chronic lung problems and was also deaf and blind.

Then three weeks before the murders, Mrs Buckley reported Mills for criminal damage and stealing her house keys and he sent a barrage of abusive texts to her in the days before the blaze.

Commissioner Ms Williams added: "The officers responsible for dealing with the allegation failed to utilise information from previous incidents involving Carl Mills and the Buckley family, and failed to use the resources available to them.

"And at an organisational level, Gwent Police missed the wider issues which are common to domestic abuse cases, and failed to ensure intrusive supervision."

The SCR - which was compiled by barrister David Spicer - said that had Mills' history been "properly researched and considered" then the risks may have been "better understood".

He also said Gwent Police's arrangements for getting information from other forces did not meet recommended standards.

And referring to the police and social service workers' decision to stop treating Kayleigh as a child when she had turned 16, he added: "Children are children until they reach 18 years."

In its report, the DHR made 13 recommendations - including the need for a cultural change towards domestic abuse.

The judge who oversaw Mills' trial at Newport Crown Court described him during sentencing as "incredibly controlling and jealous" and condemned his victims to "an agonising death".

Mills was originally given a 30-year minimum sentence, but that was increased by five years by Court of Appeal judges in London.

In response to the report, Gwent Police's assistant chief constable Lorraine Bottomley said: "The crime committed by Carl Mills was horrendous and our thoughts remain with the victims' family at this difficult time.

"The reports published today state that it's impossible to determine if these tragic deaths could have been prevented if we had done anything differently - however we accept that our service fell short of what the family could have expected and we are truly sorry for that.

"The police service and other partners manage risk on a daily basis.

"In a typical month, Gwent Police investigates 1,000 reports of domestic abuse, 185 missing children cases, and around 60 reports of abuse or neglect towards children and other vulnerable people.

"In addition to this we supervise around 500 registered sex offenders living in our communities.

"The priority is to learn from what went wrong in this case and to improve our systems to minimise the chances of this happening again.

"We have extended the training we deliver on domestic abuse and child sexual exploitation, with particular emphasis being put on the importance of front-line officers and their supervisors.

"In the last year the force has invested in the biggest transformation of its IT systems in a generation, making it much easier for officers to store and access police information electronically and in one location.

"We have reviewed our policy on the use of the Police National Database (PND) to make it clear to staff that if a suspected abuser lives, or has lived, outside the force area, then a PND check must be made.

"In recent years we have made significant improvements in our arrangements for working with partners in social care, health and the third sector to protect vulnerable people.

"Most notably we have invested in dedicated resources to tackle vulnerability associated with domestic abuse, missing children and child sexual exploitation.

"Our work in these areas has been recognised as good practice and we are now seeking to develop even better arrangements by working with our partners towards better integration of services and broadening our scope to cover all areas of protecting vulnerable people."