Mystery Pups - Diamond Dogs by Jodie Mellor. 3 adorable pups - 1 big mystery. The mystery pups arrive in Sleuth City just in time to witness a jewellery store break-in. The thieves get away - but the Mystery Pups are soon hot on the trail of the gemstones! At the very bottom of the back cover in tiny writing it says 'not for resale', so presumably these books were initially produced as a give away, promotional item. Suitable for children of approx 5-7 years.