Possible Clues:

• He solves “The Murder of Roger Ackroyd”
• 'Murder on the Orient Express' detective
• 'Little grey cells' detective
• 'The Mystery of the Blue Train' solver
• Detective finds headless writer in vessel
• Christie's Belgian
• No time for wildly enjoyable event about to be hosted by prize solver
• Agatha Christie once described him as a 'detestable, bombastic, tiresome little creature'
• 'Evil Under the Sun' sleuth
• 'Thirteen at Dinner' detective