For eight months no clue could be found to the perpetrators of the act; but on 13 January 1883, Carey was arrested and, with 16 other people, charged with a conspiracy to murder public officials. When arrested he was erecting a mortuary chapel in the South Dublin Union, and the work was then carried on by his brother Peter Carey. On 13 February, Carey turned queen's evidence and betrayed the complete details of "the Invincibles" and of the killers in the Phoenix Park. His evidence – together with that of another informer, getaway driver Michael Kavanagh – resulted in the execution by hanging of five of his associates.