The case of Oscar Slater, a German-Jewish immigrant convicted of murdering an elderly woman in Glasgow in 1908, has long been known as a famous miscarriage of justice, almost entirely because of Sir Arthur Conan Doyle’s involvement in the campaign to free him.

Without the author of Sherlock Holmes adding his considerable weight to the campaign, it is quite probable that Slater would never have been released and his story long forgotten. Even so, he served almost nineteen years in jail, mostly at hard labour, breaking granite rocks at Peterhead Prison, before being freed, reluctantly, by the Scottish legal authorities, some of whom had probably known he was innocent all along.

Slater was fingered for allegedly breaking into the first-floor apartment of a wealthy elderly spinster called Marion Gilchrist and battering her to death during the few minutes her maid had slipped out to buy an evening paper. It was supposed that she had been murdered for her jewellery, though only a brooch was taken. When it was discovered that Slater had recently pawned such an item – though he had actually done so before the murder – the Glasgow police set off on his trail.

Their suspicions seemed to be confirmed when Slater booked a passage for the United States on board the Lusitania. They chased him to New York, taking with them several possible witnesses, including Gilchrist’s maid, who had actually come face to face with the murderer as she returned from