Agatha Christie Wiki

In the Miss Marple short story The Tuesday Night Club, Mr Hargraves is an acquaintance of Jane Marple and likely to be a fellow resident of St. Mary Mead as she said he lived "up at the Mount".

Miss Marple recounted that when Hargraves died, he did not leave his money to his wife. Instead, his entire estate was willed to another woman whom he had been living with and with whom he had five children. Mrs Hargraves never even knew this affair was going on. Even more surprising, this other woman was a former housemaid whom Mrs Hargraves thought had been quite diligent and reliable.

Miss Marple, who relied a lot on pattern matching with a "village parallel", saw that the Hargraves saga fitted the case of Albert Jones and surmised that Jones had murdered his wife because he was having an affair with the maid.

Hargraves occurs again as a village parallel in The Murder at the Vicarage. This time he is referred to as "Major Hargraves" and has quite precisely the same backstory about a secret establishment with a former housemaid who gave him five children. Here there are added details that he is a churchwarden and a highly respectable man with a wife and daughter who were quite shocked to discover his secret.