In The Case of the Obliging Tourist, Otto Cermak ran a small newspaper and tobacco shop on Tottenham Court Road. He also provided on accomodation address for customers. The Contessa di Malliori received parcels at his address under a cover none of "Mary Jones". These parcels came from France and contained smuggled and even stolen pieces of jewellery sent by her accomplice Carlo Antonio Barrosa who took advantage of innocent and unsuspecting English tourists to bring them to England and then send then to Cermak by post.
At the end of of the story, Gaskin mounted a sting operation and arrested the Contessa when she turned up at Cermak's to collect a parcel. Cermak insisted that he did not know what was going on and this may have been true.