When going through his records, Foster became suspicious that Cantani, a dancer by occupation, should spend several months pay on an airfare to visit London for only a week. His suspicions increased when Foster learnt that Cantani was a friend of a wealthy emerald mine owner Jose da Silvaro, whose brother in London who looked after his European business interests. Cantani came to London again and again over the next few months. During each visit, Cantani would declare and pay duty for a few inferior emeralds. Detailed searches of her luggage yielded nothing but Foster became convinced that there must be a smuggling racket going on and approached Air Commodore Raymond about his suspicions.