Books in the Ayesha Dean Mysteries series

Ayesha Dean wants to be a detective when she grows up. But that's still a long while away. So, a trip to Istanbul with her best friends should have meant visits to ancient ruins, exploring magnificent mosques and palaces, and eating the best doner kebab in town. But when Ayesha discovers a mysterious note hinting at a hidden treasure, their relaxing holiday gets a whole lot more dangerous. An ancient artefact of untold value has been lost for years, but Ayesha isn't the only one searching for it. Someone else wants it at all costs and will take down anyone who gets in their way. Can Ayesha crack the code before it's too late?