Title sleuth

[algren]

I need to learn the title & author of an old detective novel. Story takes place in Egypt. An English lady disappears right by the sphinx and later it comes out she has been kidnapped by a secret political organization hiding inside the sphinx's body. Could you by any chance help me? I can give further details if need be.

 

[dragondrool]

Perhaps it's one of the Elizabeth Peters mysteries? Many of those are set in Egypt, particularly the Amelia Peabody books.