most children murdered in this state are killed by their mother or father.

Over 70% of children killed violently are murdered by a parent, according to garda homicide data analysed by the Sunday Tribune. Of the 25 children who have been slain since 2000, 18 of these were killed by their mother or father.

In 10 of these killings, the victim, or victims, were killed by their father; in eight cases, mothers were responsible. In one crucial respect, however, the deaths of schoolboys Glen (10) and Andrew (6) Keegan were different.

Mary Keegan's frenzied use of a knife to kill her children contrasts starkly with the methods used by other mothers who have been driven to kill their children. Five of those 18 children were drowned by their mothers while one was suffocated. Comparatively, the 10 children killed by their fathers predominantly died in bloodshed. Four were stabbed to death; two received fatal beatings; while one was shot.

Three children were drowned by their father.

In April 2000, three-monthold Leilah Smullen was stabbed to death in her Newbridge home by her father, David Hickey. In July 2001, Trevor (9) and Cillian (6) Fox were stabbed to death by their father, Gregory, at their home in Castledaly, Co Westmeath.

He also killed his wife.

Eight-year-old Karl Murphy was drowned by his mother Ruth in June 2001 at Greystones beach in Co Wicklow.

The boy's mother was separated from the child's father.

She is serving a life sentence for her child's murder. Last year, Wexford sisters Mikahla (4) and Abby Grace (3) were drowned by their mother Sharon.

Mental illness Professor Patricia Casey, professor of psychiatry at University College Dublin and consultant psychiatrist in the Mater hospital, Dublin, said that it would be unfair and inaccurate to over-emphasise the significance of the method used by parents to kill their children. "One must be careful of reading too much symbolism into the methods. The key feature does appear to be severe mental illness . . . they [the perpetrators] are so clearly distraught and have lost contact with reality . . . making it inappropriate to make a judgement on their actions in the way one would of someone acting in a rational manner, " Casey told the Sunday Tribune.

"To take your child's life and one's own suggests very severe, acute, psychiatric illness. Such action may be affected by a person going untreated or someone failing to adhere to a course of treatment, " she added.

When Jacqueline Costello was tried and convicted for the October 2000 murder of her son Robert (8) at their home at Mullinavat, Co Waterford, the Central Criminal Court heard claims that her consultant psychiatrist Dr Derek O'Sullivan, "got it wrong" in not diagnosing her as schizophrenic. After reviewing the accused's files, consultant psychiatrist Dr Brian McCaffrey told the court:

"She was not getting the proper treatment at all." Costello suffocated her son, after failing in an attempt to poison him, believing the child to be the reincarnation of her deceased brother. She was found guilty but insane.

In March 2000, nine-yearold Jennifer Palmer and her six-year old sister Louisa drowned when their mother Catherine drove their car off a pier in Co Galway. She had been suffering from psychi-