The Mystery Series (The Five FInd-Outers)
The Mystery Series is all about the Five Find-Outers and Dog, a group of children who solve mysteries in the fictitious village of Peterswood. Larry and Daisy (Laurence and Margaret Daykin) together with Pip and Bets (Philip and Elizabeth Hilton) meet Fatty (Frederick Algernon Trotteville) in The Mystery of the Burnt Cottage, the first in a fifteen book series.
When they set about finding out who lit the fire, Bets decides to call them the Five Find-Outers. And dog. Fatty has a dog named Buster, a small black Scottish Terrier. Together the gang solve the mystery, much to the annoyance of Mr Goon, the village policeman, who can't stand the kids and particularly hates that "nasty yappy little dog."