Mike Berry: Killers who claim their victims in one explosive outburst

Most readers have heard of serial killers and will know they are classified as such if they follow a clear pattern of killing strangers on at least three separate occasions, usually with a decreasing cooling-off period between each attack.

Spree killers are different. Usually spree killers kill their victims in one explosive outburst, as shown by Michael Ryan at Hungerford, who shot dead 16 adults, studiously avoiding killing any children; or Thomas Hamilton, who killed children and teachers in a Dunblane school.

The fact that we remember their names is because of the brutality of their acts and the infrequency this type of incident occurs. Ninety-nine per cent of spree killers are male and white, and often they set themselves up to be killed by the police, or simply shoot themselves dead.There have been fewer than 500 spree deaths worldwide in the past 50 years, while the figure for serial killers is far higher, with several thousand victims worldwide.

What separates spree killers from other killers is that they kill in one violent, explosive episode, usually lasting a few hours. Often they will kill significant others in their lives first and then generalise to the target population. School and student campuses are often chosen because of their obvious vulnerability and poor security. Virginia Tech covers 2,500 acres. Schools usually have little security.

Most spree killers have a grudge directly or indirectly against the target groups. The spree killer is likely to have an obsession with guns to the extent that it is more important than any other relationships, including partners. Often they are depressed and angry, but rarely mentally ill.

The typical spree killer is in his late twenties or thirties, socially isolated or distanced from people, in other words a "loner". However, the authorities are faced with a problem: it is difficult to identify potential spree killers because they are so rare. Nevertheless, there is an argument for personal interview of potential gun-licence holders. The spree killer is unlikely to have committed any previous serious offences, despite the fact that one-third of the male population have a criminal conviction of some kind. However tragic they may be, statistically speaking, most people will never be victims of a spree killing.

The solution to the problem is the containment of guns in secure settings, rather than the American model - that anyone, in theory, can have a gun. The notion that guns arecarried for self-defence is somewhat lame when fewer than 1 per cent of American homicides occur as a direct result of self-defence. Yet that is the reason offered by the "Gun Lobby". Sadly, it seems the situation in the US will not improve as the all-powerful National Rifle Associationcontinues to pile pressure on their sponsored politicians.

Mike Berry is a chartered clinical and forensic psychologist and a senior lecturer at Manchester Metropolitan University

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