What kind of future awaits Jessica and Jack?

The murderous carnage wreaked by PC Karl Bluestone shocked us all. But it is the surviving children who must live with the consequences

On Tuesday, Karl Bluestone hanged himself after bludgeoning to death his wife, Jill, and two of his four children, 18-month-old Chandler and three-year-old Henry. A third son, Jack, seven, suffered serious head wounds. Jessica, six, escaped, crying, "Help! My daddy's trying to hurt me."

Gregor and Christine Bluestone have described their son as "devoted to his children ... and filled with love for his wife", words that only underline the lack of comprehension that such carnage often incurs. Suggestions of marital discord and domestic violence have occupied much of the coverage since, some of it voyeuristic. What has received little attention, however, is the life after death that awaits Jessica and Jack. They were not only probable witnesses to murder but they have also, overnight, lost father, mother, siblings, family and home as well as that essential anchor in childhood – a trust in the security of attachment.

As many as 50 children a year in this country witness the death of one parent at the hands of another. Inevitably, as well as the grief and all the overwhelming, baffling emotions that a child experiences when bereaved at such a young age, there is indescribable distress at seeing one of the two most important people in your life cut down the other in her (and it's usually her) prime.

According to Dora Black, co-author of the study of When Father Kills Mother, a definitive study of 425 children whom, since 1987, have been affected by parental murder, those who actually witness the event are far more likely to be affected by post-traumatic stress disorder. The syndrome may reveal itself in nightmares, repetitive play, aggression and behavioural problems. It is, says Dr Black, "the brain's response to horrific events over which a child is helpless to act".

But how do we help children to cope with such horrific experiences? Can they ever live normal lives again? "What we have learnt about children who may be suffering from PTSD is that there are very few services which can respond when they find the courage to talk," says Renuka Jeyarajah-Dent, director of The Bridge Child Care Development Service, "for instance, when they themselves become parents.

"Children also need acknowledgement of the good parts of the parent who killed. They carry the same genes so, if they begin to see themselves as 'bad', this can reverberate throughout their lives."

When Father Kills Mother, which Dr Black wrote with her colleagues Jean Harris-Hendricks and Tony Kaplan, contains a follow-up study of 56 boys and 41 girls. Instead of stability, three-quarters had been moved on within the first year, some several times. Sixty per cent were in foster care or children's homes. The spectre of domestic violence casts a long shadow. In two-thirds of the families there had been long-standing conflict. The trigger for murder was given as sexual jealousy (36 per cent of the cases); a threat to leave (23 per cent); alcohol (20 per cent) and mental illness (14 per cent).

"It's important that the meaning of attachment and a sense of continuity is restored otherwise the healing process is considerably slowed down," says Tony Kaplan, a consultant child psychiatrist. "We are talking about damage limitation, not recovery."

In addition to a lack of training and resources, vulnerable children are often surrounded by adults with "powerful needs to deny, repress or distort agonising realities", inflicting further wounds. "Children don't want their substitute parents to know about their nightmares and fears," Dr Black says. "Many adults can't cope with the distress of a child, so they pretend it doesn't exist."

Children also often suffer guilt that they were unable to protect a parent. Sometimes, there is hostility from relatives who see themselves as landed with a difficult child. Loss and fear become tragically recurring themes.

In other cases, particularly ones where the offending parent has been convicted of manslaughter rather than murder, the child returns to live to the parental home once the sentence has been served. In one not untypical case from the Traumatic Stress Clinic set up by Dr Black in the early 1990s, a father murdered the mother and gave himself up to the police. His stepdaughter was immediately returned to her natural father. Her two half-sisters were sent to relatives hundreds of miles away without any of their possessions. The children asked no questions, so were given no information.

Philippa was four when she witnessed her mother's death. After her father's release from prison she lived with him, running away at 14, depressed and self-mutilating – in flight from his beatings. "She knew that if she did not leave, she would drive her father to kill again. To protect him, rather than herself, she left home," the co-authors of the book explain.

Some children have to accept a parent's account. Jonathan, 14, was told by his father that his mother had been unfaithful, implying she brought about her own death. In spite of his problems at school, Jonathan's father refused help for his son.

Each area health authority now has a child and adolescent mental health service. Services remain acutely strapped for cash, partly because the money has not been ring-fenced. The country also has a desperate shortage of child psychiatrists and psychologists. As a result, a traumatised young person can be on a waiting list for up to 18 months.

"If we intervene early in mental health problems, the prognosis is good yet the small amounts to develop the services are not there," says Dinah Morley, deputy director of Young Minds, the mental health charity. "As a result, it costs society a fortune in terms of truancy, youth crime, drug taking, teenage pregnancy and family disruption."

In the case of the children who witness a parent's murder, even after therapeutic help, the scars remain deep. Jane was five when she saw her father kill her mother. She was returned to his care, aged seven, when he was released from prison. He treated her brutally.

"For me, everything always relates back to that first moment when life's unpredictability was revealed," Jane has written, recalling her mother's death. "Life will never be that precious or interesting again and I miss that as much as I miss her."