the Stirling-based council, complaining that the region's primary staff had "shown great vigour and enthusiasm" in pursuing a campaign against him.
Copies of the letter were sent to primary heads in the area. In it Hamilton claimed he had alerted Dr Ball to the situation six months earlier when, he alleged, teachers at Bannockburn primary had told pupils and parents he was a pervert.
Chillingly, he said the education department's response that teachers should make no statements that they could not substantiate was "too little too late".
Hamilton's letter to Dr Ball then added: "At Dunblane primary, where teachers have contaminated all of the older boys with this poison, even former cleaners and dinner ladies have been told by teachers at school that I am a pervert. There have been reports at many schools of our boys being rounded up by staff and even warnings given to entire schools by headteachers during assembly. "
It is now believed he intended to wreak his revenge during assembly when many more of the school's 700 pupils would have been present, but that he arrived too late.
Dr Ball was not the only recipient of Hamilton's correspondence. Michael Forsyth, the Scottish Secretary who is the local MP, and George Robertson, his Labour shadow who lives in the city and whose three children went to the primary school, had representations from him.
These culminated in a letter dated March 7 sent to the Queen in her capacity as patron of the Scout Association which dismissed Hamilton as a scout leader in 1974. It was despatched almost exactly a week before he gunned down Dunblane's Primary 1 class.
Hamilton's activities spilled across central Scotland and beyond. He was granted school lets to run his boys' clubs in Fife, Lothian and Strathclyde schools as well as in Central Region - with parental suspicions and Hamilton's obsessive reactions mounting in almost equal measure.
But there was no mechanism for the authorities to pass information about Hamilton on to each other, a loophole now almost certain to be plugged.
Dunblane is a dormitory town, popular with professionals working in Glasgow and Edinburgh, so the tragedy has had repercussions outside the immediate area.
Professor John MacBeath of Strathclyde University, known throughout the country for his work on school effectiveness, lost his niece in the carnage; The TES Scotland office in Edinburgh was telephoned by a caller from Cologne desperate for news about his nephew at the school but unable to get through on the emergency line; a student teacher in Edinburgh was excused from her placement because she had been baby-sitting one of the victims days before.
The ripples also reached the Scottish Borders. Ron Taylor, the Dunblane head praised by police and politicians, was a primary head in Hawick before moving to Dunblane three years ago.
John Oates, the retired head of St Modan's High in Stirling, was one of many to be touched indirectly by the events last week - his son had attended one of Hamilton's sports groups at the High School of Stirling five years ago.
Mr Oates, who now works for the Catholic Education Commission in Scotland, had pulled his child out after just one meeting when his wife expressed her suspicions. He reported his experience to the educational social worker at his school to be told: "Don't touch that guy with a bargepole - and, if he ever tries to get into the school, do all you can to keep him out."
The High School head had attempted to stop Hamilton running his club there. But Central Region said it could do nothing because he had no criminal record and there was no evidence of wrong doing.
The council by this time was wary of tangling with Hamilton: it had already had its knuckles rapped over an earlier decision to stop him using schools. Hamilton took his case to the local government Ombudsman, backed ironically by 100 local parents. The Ombudsman upheld his appeal in 1984, criticising the authority for acting on nothing more than "gossip".