THE murder of Lawrence Haggart presented Central Scotland Police with one of the most baffling crime scenes its officers had ever encountered.

A strong, athletic young man had been brutally beaten to death in his own home while his two brothers slept upstairs. There was no sign of a forced entry and no signs of struggle.

With his criminal history, Brian Beattie was an immediate suspect and was questioned the day after the incident, even before the 15-year-old victim's life support machine had been switched off.

A particularly gruesome aspect of the crime remains a mystery. Police found the number 110 written in ink on the victim's palms and bizarre marks gouged in his shoulder.

When blown-up photographs of the shoulder injuries were studied, it was spotted that the wounds, made by a sharp implement like a key, also resembled the number 110. A senior detective came up with three theories:

q The numbers might relate to the Old Testament. Leviticus, Chapter 1, Verse 10, states: ''And if his offering be of the flocks, namely of the sheep or of the goats, for a burnt sacrifice, he shall bring it a male without blemish.''

q The attack on Lawrence happened around 1.10am and Beattie, believing he would never be caught, may have left a cryptic ''time-print'' of his crime.

q It may have been a reference to the rule where an accused must be tried within 110 days of being committed for trial. Beattie had been through the legal process often enough to be familiar with it.

But only Brian Beattie knows the answer.

One year after the murder, Detective Superintendent Joe Holden took over the case. In four months, he meticulously reviewed the evidence and concluded Beattie remained the strongest suspect. To build up a complete account of his criminal past, detectives interviewed everyone who had dealings with him.

Mr Holden's determination, and his rigorous attention to detail, took him as far as the FBI headquarters in the United States to have a hair found at the scene tested, although it proved to have come from Lawrence.

But as the profile of Beattie emerged, the more confident police became that he was the killer.

A murder squad source said: ''More and more, the picture we built up described Brian Beattie as a psychopathic monster. Beattie had developed this unique crime where he preys on young men and boys. Lawrence's murder was his peak. That's where he really got his kicks.''