Murder in Mesopotamia

Murder in Mesopotamia - Agatha Christie

In Murder in Mesopotamia, Christie takes us again to a location she's very familiar with - an archaeological dig near Hassanieh, Iraq.

 

To go into the details of this Poirot story would spoil the read for some so I won't.

However, there is one question I have that has driven me nuts every single time I have read or re-read this book:

 

How did she not know?!?!?