In the short story The Adventure of the Dartmoor Bungalow (later, chapters 3 and 4 of The Big Four), Saunders is a representative from a Prisoners' Help Society. Soon after Robert Grant was released from prison, Saunders approached him and helped him get a position as a servant of Jonathan Whalley at his house "The Granite Bungalow" at Hoppator in Dartmoor. Saunders also made him a gift of a pair of boots.
It later turned out that Saunders was a persona adopted by Claud Darrell, Number Four of the "Big Four" criminal syndicate. He had taken on the role of Saunders in order to set Grant up to take the blame for the murder of Jonathan Whalley.