Customs officers at the Tema Yam Park grew suspicious on Thursday 7 March 2019 when large quantities of yam boxes were brought in for export to the United Kingdom.[1][2] They called in Narcotics Control Board officers at the port, and the first opened box revealed yams packed over a compressed substance wrapped in yellow cellophane.[1][2] Searching every box, the officers found 5,851 compressed slabs of leaves suspected to be cannabis, which NACOB called the biggest narcotics bust in the country’s history.[1][2]

Two freight forwarders handling the shipment, Dominic Kojo Amenyo and Osae Akotua, were arrested and handed to the Tema Port Police for investigation.[1][2] Amenyo told investigators he was helping his colleague Osae process the yams for export to London and knew nothing of the concealed drug, while Osae said a third forwarder named only as Bright had asked him to handle the documents.[1][2] NACOB executive secretary Francis Torkornoo said each one-kilogramme slab was worth £5,000 on the United Kingdom street market, putting the haul at £29.2 million, and that the search for Bright and the exporters continued.[1][2]