Death in a Desert Land by Andrew Wilson

I'm Mrs Christie. I think you are expecting me... Baghdad, 1928.

Agatha leaves England for the far-flung destination, determined to investigate an unresolved mystery: two year ago, the explorer and the writer Gertrude Bell died there from a drugs overdose. At the time, the authorities believed that Bell had taken her own life, but a letter now unearthed reveals she was afraid someone wants to kill her... In her letter, Bell suggests that if she were to die the best place to look for her murderer would be Ur, the archaeological site in ancient Mesopotamia famous for its Great Death Pit.

But as Agatha stealthily begins to look into the death of Gertrude Bell, she soon discovers the mission is not without its risks. And she has to use all her skills to try and outwit a killer who is determined to stay hidden among the desert sands... '