Joan Smith: What's a nice guy like Karl Bluestone doing in a crime like this?

They are only two little words, but they explain so much. Without them, it is almost impossible to make sense of the actions of the off-duty policeman from Gravesend who murdered his wife and two of his four children last week.

Karl Bluestone was described after the killings as a devoted father and dedicated officer, reinforcing the atmosphere of shocked disbelief that propelled the case on to the front pages. How could this "jovial" PC, as colleagues described him, batter his wife and children with a hammer and then kill himself?

The missing words are, of course, domestic violence. And once they have been uttered, Bluestone's final moments begin to assume a very different configuration. We are no longer left to puzzle over the beaming cop who took the law into his own hands before hanging himself in the garage of the family's semi; we no longer have to struggle to square his murderous behaviour with the reactions of his neighbours, who could not believe that such a doting father had harmed his kids. For as soon as you place this incident in the context of that horribly common crime, wife-beating, you can be sure of several things.

One is that there had been a long history of rows, incidents in which Jill Bluestone was verbally abused and threatened; some time last year, neighbours saw her run from the house with her youngest child in her arms, pursued by her furious husband. In fact, Bluestone had twice before been arrested for attacking his wife. Another is that the marriage was on the verge of disintegrating; the house had been put up for sale and then withdrawn from the market as the couple struggled to reach an agreement about Mrs Bluestone's desire to leave. Why, then, did early reports of the murders present the Bluestones as a model family on whom these events had been visited like a bolt from the blue?

It is instructive to compare those reports with the treatment of a similar case in California only two weeks ago, when a 27-year-old man stabbed five members of his family to death, including his pregnant wife, and went on the run with his three-year-old son, whom he also subsequently murdered. No one was in any doubt that this was a story about domestic violence, but then Nikolay Soltys was an unemployed Ukrainian immigrant, not your friendly local bobby. The state governor denounced Soltys as a "coward", in contrast to Bluestone's superior officers in Kent, who struck a jarring note when they described the dead policeman as "committed and enthusiastic".

The incredulity that greeted Bluestone's actions is predicated on an avuncular, Dixon-of-Dock-Green image of the police that is decades out of date; modern police officers do a stressful job in a macho culture that militates against someone admitting that he or she needs help. Bluestone finished a shift only hours before launching his lethal assault on his wife and children, which suggests either that he underwent an astonishing transformation on the way home, or that his colleagues overlooked symptoms of mounting tension.

It is not even as if his actions are unprecedented. Bluestone is the ninth British man to murder some or all of his children in the last two years; I don't have room to list them all, but Julian Philpott from South Wales killed himself and his two sons in August 1999 after a custody dispute, while David Price from Bromsgrove gassed himself with his son and daughter a couple of months later.

It is customary to describe such events as tragedies, yet they are just about the most serious crimes imaginable, murder-suicides in which a depressed or angry man (very often both) is so determined to retain control of his family that he is prepared to go to the extreme of destroying them. The confused response to PC Bluestone's murders shows how unwilling we are to acknowledge this behaviour for what it is. On the contrary, the accolades heaped on the brattish American rap star Eminem, whose lyrics include violent fantasies about murdering his wife, are evidence of our tendency to trivialise it.

Home Office figures suggest that one woman in four experiences domestic violence during her life, while two are killed each week by current or former partners. This, and not some inexplicable accident, is what happened to Jill Bluestone on Tuesday evening. She and her children are the latest victims of a type of violence our society does not want to recognise, and the only certainty is that they will not be the last.

Porn merchants take over Fleet Street

There was a gloating quality to the reporting of these events, both on TV news and in newspapers, that was quite hard to stomach. "Daddy's trying to hurt me" was the headline in The Sun, using the words of Bluestone's six-year-old daughter Jessica (who raised the alarm and survived the attack) to create an emotional charge. The paper devoted five pages to the murders, while The Mirror published a colour picture of the children, grinning into the camera, with their names and fates superimposed ("Chandler, 1, dead").

This is the pornography of violent death, in which gruesome details of killings are offered to readers as an occasional alternative to intimate revelations about people's sex lives. I know August is a slow month for news, but even I was astonished when a claim that two Big Brother contestants had had sex – "Helen and Paul bonk" – filled a recent front page, along with an account of their favourite positions. Each set of revelations is as distasteful, in its own way, as the other, besides making a mockery of all those denunciations of Richard Desmond, current owner of the Express titles. Who could be a more suitable proprietor for a tabloid newspaper these days than a really experienced pornographer?

The racists of Oz

It was an unusually bold stroke on the part of the Australian government to storm the Norwegian ship, below, carrying more than 400 refugees immediately before the UN-sponsored World Conference Against Racism opened in South Africa. One of the things the conference is being asked to do, by organisations such as Human Rights Watch, is to recognise discrimina-tion against asylum-seekers as a con- temporary form of racism. And it's hard to think of a more overt form than using heavily armed special forces to drive desperate men, women and children out of your territorial waters.

Ordinary Australians have responded by offering overwhelming support to their nasty government. This is a country that locks up refugees, including children, in horrible detention centres; its treatment of its own aboriginal population, who owned the land until displaced by white settlers, is nothing short of disgraceful. (Back in the 1950s, the then Australian government even allowed Britain to let off atomic bombs in aboriginal hunting grounds, expressing surprise when families were subsequently discovered camping in the craters.) Out and proud seems to be Australia's motto when it comes to its long record of racial discrimination.

Unbridgeable gulf

"Jump, bitch, jump," exhorted angry drivers when a woman threatening suicide held up traffic across a bridge in Seattle. And she did, breaking her back as she plunged into the lake below. Police negotiators expressed astonishment that she leapt, after three-and-a-half hours of trying to talk her down. But who can blame her for finally losing her faith in human nature?