Death in the Square — Ardath Mayhar

The upper-class inhabitants of the locked-gate community called Holroyd Square in Templeton, Texas, are used to their sedate, private lives-and the equally private secrets that each of them keeps hidden from the others. But when a vicious blackmailer rudely interrupts their existence, and then is found murdered in the Square, the police must be called, and only Assistant Chief Wash Shipp can uncover the killer and save their tattered reputations. A psychodrama in the best Agatha Christie tradition!