Greed and Materialism

The desire for wealth—whether through Hannaford's secret ink formula, the diamond necklace, or the blackmail money—drives the criminal schemes and reveals the corrupting influence of material gain.

The potential fortune from Hannaford's discovery hints at financial motives behind the murder.

Mrs. Whittingham's fraudulent acquisition of a £3,900 diamond necklace illustrates the theme of greed and the pursuit of luxury through deceit.

The diamond necklace worth nearly £4,000 drives the crime and the subsequent investigation.

The potential fortune from Hannaford's ink invention drives suspicion that he was murdered for it.