he was again arrested in sept 1865, as part of the general purge of fenian leaders, based on information provided by john warner, an ex-military pensioner. the trial of john lynch and co-defendant brian dillon starting on 18 december 1865 with isaac butt as their legal counsel. the charges were "in one indictment with having conspired to depose the queen, &c., and with illegally drilling and being drilled in furtherance of that design". lynch was accused of being a captain (denoted as "b") in the irish republican brotherhood. both were found guilty, based primarily on the testimony of informants although john warner's account was very weak and unsatisfactory under cross examination. at this time, john lynch was seriously ill from tuberculosis. at his sentencing, john disputed the testimony of john warner, saying he had never learned to use a rifle and said "if, having served my country honestly and sincerely be treason, i am not ashamed of it. i am now prepared to receive any punishment british law can inflict on me." both defendants were sentenced to 10 years' penal servitude.