Ittai Gradel says he sold on some of the gems he thinks came from the British Museum. A mission to hunt them down leads the team through the backstreets of Paris and to a small town in Germany. Presenter: Katie Razzall Producers: Darin Graham, Ben Henderson and Larissa Kennelly Production Coordinator: Gemma Ashman Mix and sound design : James Beard Composer: Jenny Plant Exec-producer: Joe Kent Investigations Editor: Ed Campbell Series Editor: Matt Willis Commissioning Executive: Tracy Williams Commissioning Editor: Dan Clarke