Setting up a private army known as the Force Publique, Leopold had squeezed revenue out of the people of the territory through a reign of terror in the harvesting and export of rubber and other resources.In trade, Belgium shipped guns, whips (cocote) and other materials to the Congo, used chiefly to suppress the local people.
His father, Captain Roger Casement of the (King’s Own) Regiment of Dragoons, was the son of a bankrupt Belfast shipping merchant, Hugh Casement, who later moved to Australia.
Captain Casement had served in the 1842 Afghan campaign.
He then made efforts during World War I to gain German military aid for the 1916 Easter Rising that sought to gain Irish independence.
In Africa as a young man, Casement first worked for commercial interests before joining the British Colonial Service.
In 1890 Casement met Joseph Conrad, who had come to the Congo to use a merchant ship, Le Roi des Belges, to recover a European from a trading post on the upper reaches of the Congo River.
Both had come inspired by the idea that "European colonisation would bring moral and social progress to the continent and free its inhabitants 'from slavery, paganism and other barbarities.' Each would soon learn the gravity of his error." Conrad published his short novel, Heart of Darkness, in 1899.
Casement would later take on a different kind of writing to expose the conditions he found in the Congo during his official investigation for the British government.
In these formative years, he also met Herbert Ward, and they became longtime friends.
Using violence and murder against men and their families, Leopold's private Force Publique had decimated many native villages in the course of forcing the men to gather rubber and abusing them to increase productivity.
Casement's report provoked controversy, and some companies with a business interest in the Congo rejected its findings, as did Casement's former boss, Alfred Lewis Jones.
In 1891 he was appointed as a British consul, a profession he followed for more than 20 years.