Casement confided his personal papers to Dr Charles Curry, with whom he had stayed at Riederau on the Ammersee, before he left Germany.
He departed with Robert Monteith and Sergeant Daniel Beverley (Bailey) of the Irish Brigade in a submarine, initially the SM U-20, which developed engine trouble, and then the SM U-19, shortly after the Aud sailed.
According to Monteith, Casement believed the Germans were toying with him from the start and providing inadequate aid that would doom a rising to failure.
He wanted to reach Ireland before the shipment of arms and to convince Eoin MacNeill (who he believed was still in control) to cancel the rising.

Casement sent John McGoey, a recently arrived Irish-American, through Denmark to Dublin, ostensibly to advise what military aid was coming from Germany and when, but with Casement's orders "to get the Heads in Ireland to call off the rising and merely try to land the arms and distribute them".
McGoey did not reach Dublin, nor did his message.
His fate was unknown until recently.
He joined the Royal Navy in 1916, survived the war, and later returned to the United States, where he died in an accident on a building site in 1925.

In the early hours of 21 April 1916, three days before the rising began, the German submarine put Casement ashore at Banna Strand in Tralee Bay, County Kerry.
Suffering from a recurrence of the malaria that had plagued him since his days in the Congo, and too weak to travel, he was discovered at McKenna's Fort (an ancient ring fort now called Casement's Fort) in Rahoneen, Ardfert, and arrested on charges of high treason, sabotage and espionage against the Crown.
 He sent word to Dublin about the inadequate German assistance.
The Kerry Brigade of the Irish Volunteers might have tried to rescue him over the next three days, but had been ordered by its leadership in Dublin to "do nothing" —not a shot was to be fired in Ireland before the Easter Rising was in train. "
He was taken to Brixton Prison to be placed under special observation for fear of an attempt of suicide.
There was no staff at the Tower [of London] to guard suicidal cases."

At Casement's highly publicised trial for high treason, the prosecution had trouble arguing its case.
Casement's crimes had been carried out in Germany and the Treason Act 1351 seemed to apply only to activities carried out on English (or arguably British) soil.
A close reading of the Act allowed for a broader interpretation: the court decided that a comma should be read in the unpunctuated original Norman-French text, crucially altering the sense so that "in the realm or elsewhere" referred to where acts were done and not just to where the "King's enemies" might be.
Afterwards, Casement himself wrote that he was to be "hanged on a comma", leading to the well-used epigram.

During his trial the prosecution (F. E. Smith), who had admired some of Casement's work before he went over to the Germans, informally suggested to the defence barrister (A. M. Sullivan) that they should jointly produce what are now called the "Black Diaries" in evidence, as this would most likely cause the court to find Casement "guilty but insane", and save his life.
Casement refused to agree to this, and was found guilty and was sentenced to be hanged.

Before and during the trial and appeal, the British government secretly circulated some excerpts from Casement's journals, exposing Casement as a sexual deviant.
These included numerous explicit accounts of sexual activity.
This aroused public opinion against him and influenced those notables who might otherwise have tried to intervene.
Given societal norms and the illegality of homosexuality at the time, support for Casement's reprieve declined in some quarters.
The journals became known in the 1950s as the Black Diaries.

Casement unsuccessfully appealed against his conviction and death sentence.
Those who pleaded for clemency for Casement included Sir Arthur Conan Doyle, who was acquainted with Casement through the work of the Congo Reform Association, poet W. B. Yeats, and playwright George Bernard Shaw.
Jo
Casement confided his personal papers to Dr Charles Curry, with whom he had stayed at Riederau on the Ammersee, before he left Germany. He departed with Robert Monteith and Sergeant Daniel Beverley (Bailey) of the Irish Brigade in a submarine, initially the SM U-20, which developed engine trouble, and then the SM U-19, shortly after the Aud sailed. According to Monteith, Casement believed the Germans were toying with him from the start and providing inadequate aid that would doom a rising to failure. He wanted to reach Ireland before the shipment of arms and to convince Eoin MacNeill (who he believed was still in control) to cancel the rising.
Casement sent John McGoey, a recently arrived Irish-American, through Denmark to Dublin, ostensibly to advise what military aid was coming from Germany and when, but with Casement's orders "to get the Heads in Ireland to call off the rising and merely try to land the arms and distribute them". McGoey did not reach Dublin, nor did his message. His fate was unknown until recently. He joined the Royal Navy in 1916, survived the war, and later returned to the United States, where he died in an accident on a building site in 1925.
In the early hours of 21 April 1916, three days before the rising began, the German submarine put Casement ashore at Banna Strand in Tralee Bay, County Kerry. Suffering from a recurrence of the malaria that had plagued him since his days in the Congo, and too weak to travel, he was discovered at McKenna's Fort (an ancient ring fort now called Casement's Fort) in Rahoneen, Ardfert, and arrested on charges of high treason, sabotage and espionage against the Crown.  He sent word to Dublin about the inadequate German assistance. The Kerry Brigade of the Irish Volunteers might have tried to rescue him over the next three days, but had been ordered by its leadership in Dublin to "do nothing" —not a shot was to be fired in Ireland before the Easter Rising was in train. "He was taken to Brixton Prison to be placed under special observation for fear of an attempt of suicide. There was no staff at the Tower [of London] to guard suicidal cases."
At Casement's highly publicised trial for high treason, the prosecution had trouble arguing its case. Casement's crimes had been carried out in Germany and the Treason Act 1351 seemed to apply only to activities carried out on English (or arguably British) soil. A close reading of the Act allowed for a broader interpretation: the court decided that a comma should be read in the unpunctuated original Norman-French text, crucially altering the sense so that "in the realm or elsewhere" referred to where acts were done and not just to where the "King's enemies" might be. Afterwards, Casement himself wrote that he was to be "hanged on a comma", leading to the well-used epigram.
During his trial the prosecution (F. E. Smith), who had admired some of Casement's work before he went over to the Germans, informally suggested to the defence barrister (A. M. Sullivan) that they should jointly produce what are now called the "Black Diaries" in evidence, as this would most likely cause the court to find Casement "guilty but insane", and save his life. Casement refused to agree to this, and was found guilty and was sentenced to be hanged.
Before and during the trial and appeal, the British government secretly circulated some excerpts from Casement's journals, exposing Casement as a sexual deviant. These included numerous explicit accounts of sexual activity. This aroused public opinion against him and influenced those notables who might otherwise have tried to intervene. Given societal norms and the illegality of homosexuality at the time, support for Casement's reprieve declined in some quarters. The journals became known in the 1950s as the Black Diaries.
Casement unsuccessfully appealed against his conviction and death sentence. Those who pleaded for clemency for Casement included Sir Arthur Conan Doyle, who was acquainted with Casement through the work of the Congo Reform Association, poet W. B. Yeats, and playwright George Bernard Shaw. Jo
Roger Casement