When the plot failed Garnet went into hiding, but he was eventually arrested on 27 January 1606. He was taken to London and interrogated by the Privy Council, whose members included John Popham, Edward Coke and Robert Cecil, 1st Earl of Salisbury. Imprisoned in the Tower of London, his conversations with fellow prisoner Edward Oldcorne were monitored by eavesdroppers, and his letters to friends such as Anne Vaux were intercepted. His guilt, announced at the end of his trial on 28 March 1606, was a foregone conclusion. Criticised for his use of equivocation, which Coke called "open and broad lying and forswearing", and condemned for not warning the authorities of what Catesby planned, he was sentenced to be hanged, drawn and quartered. He was executed on 3 May 1606.