Who is the client in 'The Red-Headed League'?

The client in “The Red-Headed League” is Jabez Wilson, a London pawnbroker who asks Sherlock Holmes and Dr. Watson to explain the strange disappearance of his highly paid job.

Wilson had been recruited into a supposed organization that offered red-haired men four pounds a week to copy the Encyclopaedia Britannica. The unusual employment kept him away from his pawnshop for several hours each day. After about eight weeks, he arrived at the office and found a notice saying that the Red-Headed League had been dissolved.

Holmes quickly realizes that the league was an elaborate diversion. Wilson’s assistant, Vincent Spaulding, is actually the criminal John Clay, who has been using the cellar to dig a tunnel toward a nearby bank. The fake job keeps Wilson from discovering the scheme before the robbery is ready.

Wilson is the client, not the villain. John Clay is the mastermind behind the attempted burglary, while Vincent Spaulding is his assumed identity. The story first appeared in The Strand Magazine in 1891 and became one of the best-known stories in The Adventures of Sherlock Holmes.