FRESH questions have been raised over the murder of Marion Gilchrist in Glasgow more than 100 years ago.

Oscar Slater was sentenced to hang for bludgeoning the wealthy spinster to death in December 1908, yet many have held the view that his conviction was tainted.

Indeed, novelist Sir Arthur Conan Doyle was among those convinced that the accused had been innocent. The Sherlock Holmes author is said to have called upon his own detective skills to try and clear Slater's name.

Now, New York Times journalist Margalit Fox has taken another look at the case and questions the validity of the prosecution's key witness: handmaid Helen Lambie.

Miss Lambie left Miss Gilchrist's address for only 10 minutes, to buy her employer an evening paper. On returning home, she saw a well-dressed gentleman leaving the flat.

Author Margalit is convinced that Lambie recognised the gentleman and had not been entirely honest, or at least doubted what she saw.

Margalit explains: "Lambie was very secretive and unforthcoming in terms of talking about the case. In 1927, she released a newspaper statement recanting her testimony, but a short time later she recanted her recantation."

The author examined letters between Lambie and her mother and formed the view that Lambie was becoming "more and more invested in persuading herself of Slater's guilt".

Slater was blamed for the murder in what was described as a robbery gone wrong. Although there was a great deal of precious jewellery in the flat, only one item was missing: a diamond brooch.

He was sentenced to death on May 27, 1909; however, 48 hours before he was due to meet his fate, his sentence was reduced to life imprisonment with hard labour.

Following years of campaigning and investigating from Conan Doyle, the Secretary of State for Scotland authorised Slater's release on November 8, 1927

Slater was given £6,000 upon his release but refused to share his compensation with those who fought for him, including Conan Doyle. The Sherlock Holmes novelist later took him to court.

Margalit read about the case and began her own investigation, culminating in the book: Conan Doyle for the Defence, where she argues the true killer's identity was lost with the death of Lambie in 1960.

She concludes: "If I had to ask her one question it would be who she saw that night. The evidence suggests she recognised the man who left the flat. Helen told Miss Gilchrist's niece that she saw the man and that it was a highly-placed member of Glasgow society."

In 1914, city detective John Trench released documents which showed his colleagues had doctored evidence and suppressed the name of the suspect, thought to be a doctor, from witness statements.