As a young official at the shipping company Elder Dempster, Morel observed a fortune in rubber returning from the Congo while only guns and manacles were being sent in return. He correctly deduced that these resources were being extracted from the population by force and began to campaign to expose the abuses. In collaboration with Roger Casement, Morel led a campaign against slavery in the Congo Free State, founding the Congo Reform Association and running the "West African Mail". With the help of celebrities such as Arthur Conan Doyle and Mark Twain, the movement successfully pressured the Belgian King Leopold II to sell the Congo Free State to the Belgian government, ending some of the human rights abuses perpetrated under his rule.