Three Days' Terror — John Creasey

A stupid young man who is heir to a vast fortune is often more trouble than he is worth, particularly when he is a gambler and a lecher. And Arthur Pagham is soon dead -- a bullet in his heart. But he is not the only victim, for that ruthless blackmailer the Terror is at work on others too. You either submit to the Terror's demands -- or you die! Recently returned from New Zealand, Peter Ross is appalled to hear of his cousin Arthur's pointless death and agrees to help the police in their attempt to unmask the diabolical villain who casts a shadow of fear over those more indiscreet members of monied gentry. But it is not long before the Terror starts to cast his net of panic in new waters, and soon Ross and the whole country are embroiled in the Three Days' Terror.