DETECTIVES who dealt with Angus Sinclair remarked on how polite and self-effacing he came across in interviews, a mask that hid the monster within.
But there is no doubt his place in history as one of Scotland’s worst sexual, murderous predators.
Standing at 5ft 3ins, Sinclair began his criminal career simply enough with the theft of a church collection box as a young boy growing up in Glasgow.
But at the age of 16 the young man with jet-black hair soon progressed to a life of violence – strangling seven-year-old schoolgirl Catherine Reehill in 1961.
He pleaded guilty to culpable homicide and served six years behind bars.
Following his release, he went on a shocking killing spree that was to be discovered later.
But he had also carried out vile sex attacks on 11 young girls – including three rapes which were to see him convicted in 1982 for the attacks on victims aged between six and 14 and was sent back to jail.
While still in prison, Sinclair was given a life sentence in 2001 for the murder of Glasgow teenager Mary Gallacher in 1978, after compelling evidence against him. The 17-year-old was raped and stabbed as she went to meet a friend. Sinclair was linked to the crime years later following a DNA breakthrough.
Police fear he may be responsible for several other unsolved murders. Among them are the cases of Anna Kenny, 20, Hilda McAuley, 36, and 23-year-old Agnes Cooney.
However, it was the unsolved 1977 World’s End murders that Sinclair would eventually be linked to thanks to DNA evidence.
Allan Jones investigated the deaths as “man and boy”, and latterly was the senior investigating officer in the case until his retirement in 2012.
Mr Jones, who interviewed Sinclair numerous times, said: “Sinclair is a bit of an enigma. When you actually deal with him as an individual he is quite polite, self-effacing – there is nothing extraordinary about him.
“However, there is a difference between that persona and what he really is. He is probably one of the most conniving, evil and cruel individuals you would ever have the misfortune to meet – as many victims unfortunately did.”
“I think he’s involved in other murders that occurred in the 70s. There are cases where the hallmarks are the same, the methods and circumstances of the murders are similar.”
“He’s a horrendous individual who will always be a danger to society.”