The laughter of dead kings - Elizabeth Peters

The heist of the century has taken place in Egypt's Valley of the Kings, and Vicki's on/off boyfriend, Sir John Smythe, is a prime suspect.

Despite his insistence that he is no longer in the business of stealing antiquities and art objects, even Vicky isn't one hundred percent certain he has not fallen back into his old habits. Pursued by Interpol, the Egyptian police, rival gangs of illicit antiquities thieves, and (worse of all) Vicky's inquisitive boss, Anton Z. Schmidt, she and John set out on a wild chase across Europe and Egypt in an attempt to clear him by finding the real culprits and retrieving the stolen object.