H. R. F. Keating 
Inspector Ghote Trusts the Heart [EPUB ebook] 

Some crooks have tried to snatch the plump son of a business tycoon, and have accidentally made off with his playmate instead. But they’re not changing their plan: a payment is to be delivered to them or a small corpse is to be delivered to Inspector Ghote.But what kind of ransom can a mere tailor’s boy demand? And, as something more unpleasant than just a ransom note arrives from the kidnappers, are the police helping keep the boy in one piece?