In the novel Hickory Dickory Dock, Mr Hicks is the shopkeeper of a camping and travel supplies shop just down the street from the hostel at Hickory Road owned by Christina Nicoletis. Among the many strange events which had taken place at the hostel was the discovery of a rucksack which had been cut up. Poirot considered this significant. When told that most of the students at the hostel got their rucksacks from Mr Hicks's shop, Poirot also bought himself one ostensibly for a nephew.
On closer examination of the rucksack, he found that there was something strange. The item was too cheap compared with similar products on the market. On cutting the rucksack up, Poirot found a space between the inner lining and the base which had a stiffening layer of corrugated cardboard. This space was ideal for smuggling small high value items such as drugs or jewels. Poirot surmised that a smuggling racket might make a large quantity of such rucksacks and release them cheap on the market. Shops would sell them, the shopkeepers themselves may or may not be in the know. Students would buy them and travel overseas, where the rucksacks would be switched for similar ones with contraband inserted into the secret compartment. The students would then innocently bring them back into the country.