Patrick O’Donnell: The Man who Avenged the Invincibles – John Joe McGinley on story of Patrick O'Donnell who shot James Carey 'the informer' on a boat to Cape Town in 1882. https://www.theirishstory.com/2020/11/02/remembering-patrick-odonnell-the-man-who-avenged-the-invincibles/#.X6A8tFABwg4.twitter
Carey was an 'Invincible' who had informed on his comrades who carried out Phoenix Park murders in 1881. More on Carey and the Phoenix Park murders, in which the 2 most senior British officials in Ireland were stabbed to death, here: https://www.theirishstory.com/2012/07/31/the-invincibles-and-the-phoenix-park-killings-2/#.X6A9gVj7TIV
O'Donnell was not actually an Invincible or even a Fenian. That he was on the same boat as Carey to South Africa was entirely coincidental. McGinley argues that he harboured hatred of informers from his time in the Irish miners' secret society in Pennsylvania the Mollie Maguires
His trial became a cause celebre and luminaries from French writer Victor Hugo to US President Chester A Arthur appealed for clemency, to no avail. He was hanged in London in December 1883.
To that generation of Irish nationalists the story was famous, showing supposedly Fenian omnipotence, along with events such as the freeing of prisoners from Catalpa, off Australia in 1876 https://en.wikipedia.org/wiki/Catalpa_rescue
O'Donnell however, was in reality a 'lone wolf'.
His act was immortalised in the bawdy song 'Monto', "Carey told on Skin the Goat, O'Donnell caught him on the boat, he wished he'd never been afloat the dirty skite, it wasn't very sensible to tell on the Invincibles, they'll stand up for their principles all the day'."
'Skin the Goat' was the nickname of James Fitzharris, one of the Invincibles. Passage in this video of the song from 2 mins to 2:20.