The murder of roger ackroyd

Roger Ackroyd was a man who knew too much. He knew the woman he loved had poisoned her first husband. He knew someone was blackmailing her - and now he knew she had taken her own life with a drug overdose. Soon the evening post would let him know who the mystery blackmailer was. But Ackroyd was dead before he'd finished reading it - stabbed through the neck where he sat in his study...