THE AWFUL truth about Thomas Hamilton is that his murderous rampage cannot be put down to the heart-rending actions of a raving and insane monster.

Put bluntly, he slaughtered 16 innocent children and their teacher for no other reason than to get back at their parents.

Hamilton, 43, did not have a mental illness, but did have a personality disorder - one hard to detect under normal circumstances, let alone given his failure to have seen a doctor for some 20 years.

He was, it is now known, a paedophile and a loner who, for years, had only vengeance on his mind and in his heart.

On March 13, by killing children, he acted out his violent fantasies against the adults he perceived had spread rumours about him.

After studying statements and transcripts of evidence, and viewing hundreds of video tapes and photographs taken by the killer himself, Hamilton scored only six points - out of a possible 24 - when assessed as a psychopath.

It is small comfort to those questioning why the massacre took place that he showed ``significant features'' of a sadistic personality disorder in the run-up to his ritualistic, suicidal end when he used guns to solve his problems.

He was extraordinarily manipulative and cunning, and had an awesome capacity to deflect criticisms of his unhealthy interests in boys and guns on to the critics themselves.

Above all, Hamilton knew his rights - twice lodging formal complaints against police and winning one crucial case via the Ombudsman.

He believed that staff at Dunblane Primary were telling families not to send children to his boys' clubs, and he also believed parents were spreading rumours that he was a pervert, to use his own term.

It seems unlikely any sort of psychometric screening could have predicted that his way of getting back would be to massacre their offspring. But alarm bells should have rung, given all that was known about him in the tight-knit community where he lived an

d worked.

By all accounts, he was viewed as ``a weirdo'' by those who knew him. His gym classes, for instance, may have been an excuse for touching and dominating boys.

By any standards, Hamilton's upbringing was bizarre. He was raised believing his grandparents were his parents, and that his mother was his sister.

His mother Agnes, who was illegitimate, had returned to her adoptive parents soon after Hamilton's birth when her marriage broke up. They adopted him, and until adolescence he believed Agnes was his sister.

Many things in his life were similarly distorted, not least his obsessions with young boys and guns, which he held legally.

His lifestyle - calculating, determined, and obsessional - was also, in hindsight, chilling.But, although branded a loner, he did have friends across a wide social spectrum. They ranged from a TV cameraman to police officers who obtained discounts at his

DIY shop.

Today, virtually all who knew him well refuse to acknowledge anything other than an ``acquaintanceship'' - regardless of trips on his boat at Loch Lomond and visits to his house.

He is now dismissed as sinister and sleazy, especially by neighbours. They speak only of pictures of young boys displayed in his home; his penchant for wearing (and hiding behind) a grubby, hooded anorak; his leech-like ability to keep in contact; an effe

minate manner, and, above all, dismiss him as ``a bit of a creep''.

The words ``dingy'' and ``seedy'' sum up Hamilton, his habits, and his council house in Kent Road, Stirling.

Photographs taken by police after the atrocity give an insight of his sinking into an abyss. Parts of his house, strewn with pictures of boys, were as dirty as his mind. Bullets were scattered over a table, and on another a Central Scotland phone book was

open at page 57, the entry for Dunblane Primary.

One woman who sat with Hamilton in the back seat of a car on returning home from a range shoot at Inverclyde, remembers him as ``a right weirdo'', and spoke of his guns as if they were ``his babies''.

For years, when building up his arsenal, he cited target shooting as the reason for legally possessing guns. However, he was a ``fair-weather'' shooter, an irregular attender, and would often just ``blast off'' all 12 rounds within 20 seconds when suppose

d to fire only six in two minutes.

Just 11 days before the massacre, Hamilton put 12 rounds into one target of a human when supposed to fire six rounds into two separate targets.

An unhealthy interest in boys had surfaced long before then - in 1974, when he was 21 and had been appointed a Scout leader. Two trips north ended with youngsters sharing his van overnight instead of staying in hostels.

After expulsion, and the Scouts' failure to go public on their suspicions, Hamilton fed his perverted desires against boys - and his animosity towards the Scouts - by starting his own, rival clubs.

However, his defences cracked under the barrage of wagging tongues, pointing fingers, and financial problems.

Extraordinarily plausible and always in control, he had an answer every time to inquiries, usually over complaints by parents about his improper behaviour at summer camps.

His long descent into Hell was completed when he entered the school assembly hall.