In 1925 William Gordon was released from Peterhead Prison in Scotland. Unbeknownst to the authorities Gordon smuggled out a message from fellow prisoner, Oscar Slater. The message, written on waterproof paper and hidden under Gordon’s tongue, was a plea for help. It was to be delivered to none other than Sir Arthur Conan Doyle.

Conan Doyle first heard the name Oscar Slater years earlier. He became aware of the case when Slater was sentenced to death for the murder of Marion Gilchrist.

The crime occurred on December 21, 1908 in Glasgow. There was a public outcry against the brutal murder. The police and the public wanted the crime to be solved quickly and the murderer put behind bars. Within five days the police announced that they were looking for a suspect. His name was Oscar Slater.

Slater was discovered in America. Once he was made aware of the accusations against him Slater willingly returned. He was positive that he could prove his innocence.

The trial was held in 1909. Despite the conflicting evidence Oscar Slater was found guilty of the murder of Marion Gilchrist and sentenced to death. Slater’s lawyers started a petition that urged mercy. Two days before he was scheduled to die, Slater’s sentence was changed to imprisonment with hard labor for life.

Slater’s lawyers also contacted Sir Arthur Conan Doyle. While Conan Doyle didn’t approve of Slater or his lifestyle it was clear that he was not the murderer of Marion Gilchrist. In 1912 Conan Doyle published "The Case of Oscar Slater". It examined evidence brought forward at the trial and point by point proved that Slater was not the killer.