He resided in London as procurator of St. Omer's College, and was also one of the
missionary fathers there. In 1678, on the information of
Titus Oates, he was summoned to appear before the
Privy Council, and committed to
Newgate Prison. He was put in chains and suffered great pain as a result: one of his legs became so infected that
amputation was proposed. His correspondence was seized, but to the Crown's disappointment it turned out to be completely innocuous: as he forcefully pointed out at his second trial, among at least a thousand letters taken from him there was not one which could be construed as treasonable. He was tried for
high treason with
William Ireland, in that they had conspired to kill King
Charles II, a charge fabricated by Oates and later embellished by other informers. Oates claimed that he had overheard some incriminating remarks they made at a meeting of senior Jesuits in late April 1678 in the White Horse Tavern on
the Strand: they could truthfully deny this, although they had at the time been at a meeting of senior Jesuits in the
Palace of Whitehall. As the evidence of treason was insufficient, since the Crown lacked the requisite two witnesses, he was remanded back to prison. However, in the political climate of the time, it was unthinkable that so prominent a Jesuit should be allowed to escape with his life: accordingly, he was arraigned a second time at the
Old Bailey on 13 June 1679, before all the High Court judges. He was tried together with four other Jesuit fathers (
John Gavan,
William Harcourt,
Thomas Whitebread and
Anthony Turner}. Oates and two other notorious informers,
William Bedloe and
Stephen Dugdale, were the main witnesses against them, and in accordance with the direction of Lord Chief Justice
William Scroggs, the jury found the prisoners guilty, despite their spirited defence. At the end of the prosecution case Fenwick made a vigorous protest: "I have had a thousand letters taken from me: not any of these letters had anything of treason in them. All the evidence comes but to this: there is but saying and swearing." ==Execution==