He was deeply shaken by the murder of his colleague Arthur Wolfe, 1st Viscount Kilwarden, during the Irish rebellion of 1803, especially as there was a rumour that Kilwarden had been murdered by mistake. Carleton was said by some to be the real target, in revenge for his condemnation of the Sheares brothers in 1798. The rumour was almost certainly false since the eyewitnesses to the murder agreed that Kilwarden was killed only after giving his name and office, and was in great fear of his life during the Rebellion.