The documents, which were “closed” for 100 years but are being released after pressure from families of the 16 primary schoolchildren killed, are expected to show that there were several occasions when Hamilton could have been arrested and prosecuted for assaulting boys at summer camps.

Although they confirm previous claims of incompetence among police and prosecutors, the papers are expected to debunk conspiracy theories that have gathered pace since the March 1996 killings and the subsequent inquiry under Lord Cullen. These include claims that police were tipped off that Hamilton was armed and en route to Dunblane Primary School, that he was a Freemason and received favours from Masons in the police allowing him to avoid prosecution, and that he was part of a paedophile ring that included members of the security forces.

The papers are believed to include three separate reports made by police to the procurator fiscal service between 1988 and 1993 which detail claims that Hamilton, a former scout master, had struck children at camps he ran. On one occasion, police seized a vast collection of photographs of nearly-naked boys. Police urged prosecution but no action was taken and officers were ordered to return the photographs.

The files, which also reveal the full extent of Hamilton’s letter-writing to police chiefs and politicians, including Michael Forsyth, the former Scottish Secretary, will trigger fresh criticism of the way authorities in Scotland dealt with him before the shootings.

Mick North, whose only daughter Sophie was among those killed and has been given a preview of the papers, said: “You have a situation where a number of reports are being received by the police of behaviour towards children that is worrying and which outline similar types of behaviour. Yet each incident was viewed in isolation.”

He said, however, that the papers did not “reveal anything more sinister that would imply a cover-up” and that they explained claims that off-duty police were at the school when the killings occurred. Dr North said that the documents showed that two off-duty officers had dropped their own children at the school on the morning of the tragedy; while one returned home before the shootings, another was in the school and headed for the gym when he heard shots.

The documents are also expected to lay to rest doubt about whether Hamilton took his own life, and include medical reports that he killed himself with a single shot to the head.

Michael Matheson, an MSP who has spent two years lobbying for the files to be made public, said: “I believe the documents of the greatest interest will be the police reports and previous investigations carried out into Hamilton’s behaviour, which may give rise to why and how the local police made certain decisions allowing him to keep his gun licence.” But he said that the papers were unlikely to end the conspiracy theories for everybody. “For some it will provide them with closure but for others it may only lead to more speculation and conspiracy stories,” he said.

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