The Mystery of the Burnt Cottage: Book 1 
The Mystery Series by Enid Blyton 
 
Someone has set fire to Mr Hick's cottage, but who could it be? Fatty, Larry, Daisy, Pip, Bets and Buster the dog have their very first case to solve. But it's not easy being detectives with policeman Mr Goon telling them to "clear orf". The Find-Outers are determined - they have to solve the mystery before Mr Goon does!