IN JANUARY 26th this year, Thomas Hamilton sat down in scruffy, damp Kent Road flat in Stirling and tapped out what was to be one of his final angry complaints against the world. Less than two months later he acted out the revenge he sought against a society that had "contaminated" and "poisoned" people against him.

In his neatly typed letter to the education convener of Central Regional Council, he complained that "parents had heard vague gossip" that he was a "pervert". When "previously happy people are poisoned in this way they become hostile and unapproachable," he warned.

Hamilton had been hostile and unapproachable himself for many years. In a confused childhood, he had been brought up to believe that his mother, Agnes, was his older sister. His "parents" were, in fact, his grandparents, Jim and Kate Hamilton.

His real father, Thomas Watt, now aged 65, last saw his son when he was 18 months old, when he and Hamilton's mother broke up. He has since remarried and had four more children. "I brought this monster into the world," he said yesterday. "How do I tell my two daughters and my two sons that this man is their half brother?"

Hamilton's grandfather, Jim, now aged 88, whose wife died in 1988, left the two bedroom Kent Road council flat he shared with his grandson after a row. He has not spoken to him for four years.

Hamilton's mother, Agnes, said she did not recognise the killer as her son. She had never known him to be angry or to bear a grudge. "He seemed to get on with everybody that I know of," she said.

BUT Hamilton's big problem was that he hardly got on with anyone. He was in his early 20s when he suffered his first major rebuff, being removed from the Scout Association in 1974, less than a year after he had become a leader. The grudge he felt at his dismissal never left him.

He was expelled because he was seen as irresponsible rather than because of any sexual malpractice. John Fogg of the Scout Association described why he was asked to leave. "His expulsion followed two weekend camps to the Aviemore area in 1974. During the first weekend Hamilton claimed that he and a party of eight boys had been booked into a hostel in the area. Inquiries revealed this to be untrue.

"Hamilton and the boys had in fact slept in the back of a van. The van had frozen overnight in the inclement weather and had to be towed to a garage. The boys were found to have been extremely cold after an uncomfortable night."

Former Scout Commissioner Comrie Deuchars, now aged 68 also remembers the young Hamilton. "His organising skills were dismal. He was not right for the job. There was no planning to his activities. He was in it for self glory rather than the interests of the boys."

Ever since that departure, Hamilton pursued his twin interests of boys clubs and guns. Despite the rum ours and misgivings of parents, he was surprisingly successful in setting up clubs.

One 15 year old from Stirling, who attended Hamilton's clubs held at both Bannockburn High and Dunblane High schools described what became the standard procedure in the clubs. "He used to say to us, `You should take off your T shirts and have bare tops.' So you would just have your shorts on. He used to say, `Let's see who has the best build, and you can be captain of the football team.'"

A 13 year old said: "He was really mad about fitness. He would video the gymnastics. My dad banned me from going. He used to say to me `You can come around and see my gun.' I thought he was a right weirdo."

Thomas Hamilton hired school halls - usually the gym - from three separate local authorities to run sports clubs for boys over a period of at least 10 years. One by one they became anxious about his activities and terminated the agreement.

Fife Regional Council let him the gym in two schools in the area between 1986 and 1992 for weekly sessions of five a side football and gymnastics for boys aged eight to 11. The clubs were monitored, said the council's spokeswoman, and they had no cause for concern. But in 1992, the council heard of complaints from parents over a summer camp that Hamilton had held in Dunblane. Three children had run away, apparently because of the stringency of the training. There was no suggestion of sexual abuse, but councillors had heard other stories too.

Mr Tom Dair, then education chairman and now vice convener of Fife Regional Council, took the decision to cease the lets. He said that it was an "instinctive response to a number of things that had been building up."

Hamilton complained to the Ombudsman, but was rejected because he had refused to meet councillors to explain himself.

One regular recipient of Hamilton's anxious pleading was the local MP and Scottish Secretary, Mr Michael Forsyth, who has revealed that the killer came for advice to his surgeries. "He was one of my regular correspondents."

Mr Forsyth said he had discussed Hamilton with police but they were unable to find evidence against him which could result in a prosecution.

In his letter to the minister, headed "Boys Sports Club Group Committee" - an organisation which has been described as a figment of Hamilton's imagination - he writes: "Mr Forsyth, in 20 years of operation of our lawful activity, there has never been any law breaking or any suggestion of sexual child abuse from any boys against either myself or any of my leaders. I know that sexual child abuse must be identified and the abusers rooted out as a matter of national priority and this, in concept, is wholeheartedly supported by the general public."

In another letter to parents last August, Hamilton referred to persistent rumours about him circulating in Dunblane. "I am writing to briefly explain matters and dispel any myths and gossips."

He was clearly unconvincing in his attempts. Doreen Hagger, aged 40, whose son had attended his camp, confronted Hamilton after she discovered that the boys were forced to run around naked, rub suntan oil on to Hamilton, and were stripped and thrown into the freezing loch.

Mrs Hagger spent four weeks at the camp in the summer of 1989 to keep an eye on Hamilton's activities. She said that she all her evidence, including photographs, to Strathclyde police. There were no charges.

But Mrs Hagger said: "He was in his van one day and stopped me outside my house. He said he heard I had been talking to the police. I told him that as far as I was concerned he was a pervert and should not be in charge of boys. At that he produced this gun from under his seat and pointed it at me, saying it was loaded."

She said she contacted police but was told that Hamilton had been moving the gun and had a permit for it.

During his final days neighbours who knew Hamilton noticed a change in his character; the apparently shy man of few words, who often ignored locals on the Braehead estate where he lived, suddenly became unusually talkative.

Helen Peters, who lives opposite Hamilton's Kent Road flat, said she spoke to the killer at some length only a few days before the massacre.

She and her boyfriend were taking their puppy for a walk around 11 p.m. when Hamilton emerged from the grounds of a local primary school. They shouted him over and asked for the address of a local gun club which they wanted for personal reasons.

"He said he would be delighted to help, would give us an address and pop it through the letter box," said Ms Peters. "We wondered why he was coming through the school at that time of night. He was so talkative for a guy who rarely exchanges more than a few words and never mixes."

THE president of Stirling Rifle and Pistol Club, Mr George Smith, condemned that Hamilton had been a member since at least 1987. "He was an infrequent visitor to the Whitestone Rifle Range where we do target practice.

"He was always very courteous but didn't have much to say for himself. How do you know when someone is going to flip their lid and do something like this? From what I saw he was a pretty good shot and like a lot of members had semi automatic pistols and kept them at home."

Hamilton moved into photography, mainly so that he could take pictures of the boys in his charge. He was banned from his local camera shop, which refused to develop his film. Instead he had to take it to professional film processors in Glasgow.

Staff at Ronnie Kilpatrick's camera shop in Stirling knew him well. He owned professional camera gear worth thousands of pounds and bought and sold equipment privately. He would advertise in Amateur Photographer but with little success. No one wanted to know him.

All the while, Thomas Hamilton nursed his wrath to keep it warm.