After the outbreak of the World War Casement went to the United States, whence he wrote in Oct.
"Princess, my dear, there's someone driving up the avenue!" she said, holding the casement and not closing it.
Casement, who with two companions had landed in a collapsible boat at Banna, was arrested on the 24th in a ruined fort which afterwards became a place of pilgrimage for Sinn Fein Irishmen.
This despatch failed to evoke any response from the powers, with the single exception of Turkey, but the public agitation against the Congo State regime continued to grow in force, being greatly strengthened by the publication in February 1904 of a report by Mr Roger Casement, then British consul at Boma, on a journey which he had made through the middle Congo region in 1903 (described as the "Upper" Congo in the report).
Redmond Howard, Sir Roger Casement: a Character Sketch without Prejudice (1916).
Immediately after his arrest Casement was taken to London, and on May 15 was charged at Bow Street police court with high treason, and committed for trial.
The Defence of the Realm Act and other war-time measures threw in these years a great burden of anxious work on the law officers of the Crown, including the prosecution of Sir Roger Casement for high treason at the Old Bailey.