We are at a loss to know.

Suicide in itself is a tragic, inexplicable loss that inflicts terrible suffering on the loved ones who remain.

But to take the lives of three precious young children along with your own is unimaginable.

It is impossible for us to even attempt to understand the grief of the sole remaining member of that family of five, the mother, and her own immediate family members.

No doubt many other people will also be blaming themselves for not having done more to avert the disaster, feeling sick that they did not act more decisively to halt or report the violence and the damage they could see being inflicted.

DOCS is once again the institution in the gun for failing to act more pro-actively when police reported their concerns for the family's welfare a week before their deaths.

NSW Premier Morris Iemma has said there will be a full scale inquiry into why the department did no more than make a few phone calls and fail to follow up when they went unanswered.

The police and courts also knew of the man's violent tendencies. He had been arrested for assault and released on bail. Police called to the property the previous weekend took him to Merimbula police station in the early hours of Sunday morning, and an apprehended violence order was taken out against him.

After driving him back to their home when he was released last that day, then being subjected to further abuse, the mother fled to the safety of her family in Bega. The children were not so lucky.

Many neighbours, relatives and friends also knew of the violence against the woman that had been going on for some time. No doubt they will be castigating themselves for not having done more. One has gone on record as saying what many of them probably feel, that this was a preventable tragedy.

But the hard, cold truth, is that no matter how much any or all of these people blame themselves, or perhaps others, it is not their fault.

The sole responsibility for the horrendous act lies with the man who killed his young children and himself.

Whatever his motive, whatever his reasons or attempted justifications, whatever madness drove him to it, the responsibility for his action is his and his alone.

Perhaps his father-in-law came closest to closest to judging him correctly when he said simply, "Why didn't he just take his own life, not those of his children."

We will never understand what tortured and tormented him to the extent that he could commit such an atrocity.

Was it an act of vengeance? Of desperation? Of despair? Did he see it by some twisted reasoning as an act or mercy? Certainly it does not appear to have been a cry for help. The planning was calculated and deliberate and determinedly final.