The Murder on the Links (Hercule Poirot Series)

Monsieur Renauld dies on a golf course just days after sending a plea for help to detective Poirot. Since Renauld possessed a plundered fortune, a scorned wife, a mistress, and an estranged son, there is no lack of suspects. It's up to Poirot to put the police onto the culprit before more murders occur.