Police failures in the run-up to the killings of a pregnant mother and her 23-month-old son had "more than minimally contributed" to their deaths, an inquest jury found.
Rachael Slack, 38, and her son Auden were stabbed to death by her former partner Andrew Cairns - who had a history of mental illness.
During an inquest at Derby and South Derbyshire Coroner's Court, which began last month, jurors heard that Cairns had been struggling with declining mental health since the break-up of his relationship with Ms Slack in 2009.
A jury at the inquest into the stabbing of Rachael Slack, Andrew Cairns and their son, Auden, has reached the verdict that Ms. Slack was unlawfully killed by Cairns. In part, her death was minimally contributed to by a failure to impress upon her that she was at high risk of homicide.
The jury also found Auden Slack was unlawfully killed by Cairns and in part his death was minimally contributed to by a failure to impress upon his mother that he was at high risk of serious injury or homicide, and a failure to discuss with his mother adequate steps of protection.
Andrew Cairns was found to have taken his own life.
A jury has returned the verdict that Rachael Slack was unlawfully killed by her former partner, Andrew Cairns, in 2010, and also determined a failure by the police to tell her of the high risk to her life was a contributing factor
DCI Gary Goacher of Derbyshire Police said the deaths have had a ‘massive effect’ upon the officers who dealt with Cairns and Ms. Slack prior to the stabbing.
The head of mental health charity, SANE, Marjorie Wallace CBE, has said somebody should have ‘got their act together’ and intervened when it was apparent Andrew Cairns posed a threat to Rachael Slack and their son, Auden.
The partner of Rachael Slack at the time she was killed by Andrew Cairns, has said the couple should have known police assessed Ms. Slack as being at high risk of homicide.
Robert Barlow was not informed of the assessment and believes he and his partner could have reorganised their lives accordingly.
Rachael Slack, who was stabbed to death along with her son 23-month-old Auden, was unlawfully killed by her former partner Andrew Cairns and a failure by the police to tell her of the high risk to her life was a contributing factor.
The inquest also ruled that Cairns took his own life.
The jury in the inquests into a pregnant mother, her ex-partner and their son found stabbed to death in Derbyshire have gone out to resume their deliberations.
Rachael Slack, Andrew Cairns and two year old Auden were found with multiple stab wounds at a cottage in Holbrook near Belper in June 2010.
The coroner, Dr Robert Hunter, gave the jury directions to help them reach their conclusions (verdicts) before sending them out yesterday afternoon.
Dr Hunter has told them they can return a narrative conclusion on Rachael and Auden Slack which incorporates "unlawful killing". They can also consider whether any failings by the police contributed to their deaths.
The jury will spend a second day considering verdicts at the inquest into the deaths of Andrew Cairns, his former partner, Rachael Slack, and their son, Auden.
The inquest jury have heard five weeks of evidence covering the day of the tragedy and police contact with Andrew Cairns in the days leading up to it. They have also been told about Mr Cairns' history of psychiatric problems and his care by mental health services in Derbyshire.