It was a conviction that caused him, within six weeks of the Mary Celeste’s being found, to write in an official report to the Board of Trade in London: My own theory is that the crew got to the alcohol and in the fury of drunkenness murdered the master, whose name was Briggs, his wife and child and the chief mate; that they then damaged the bows of the vessel with the view of giving it the appearance of having struck on rocks or suffered a collision so as to induce the master of any vessel which might have picked them up, if they saw her at some distance, to think her not worth attempting to save; and that they did some time between the 25th of November (the date of the last log entry) and 5th December, escape on board some other vessel bound for some North or South American port or the West Indies.

The British government accepted his view. On March 11, 1873, Sir Edward Thornton, British Ambassador to Washington, passed on to the American administration evidence assembled in Gibraltar and asserted in his covering letter: ‘You will perceive that the enquiries which have been initiated into the matter tend to rouse grave suspicion that the master and his wife and child were murdered by the crew.’

Responding to the British government’s belief, U.S. Secretary to the Treasury William A. Richardson circularised customs officials throughout the United States on March 14, instructing them to look out for any ship carrying the alleged murderers to America.

Captain James Winchester, principal owner of the Mary Celeste, fled Gibraltar after giving evidence at an enquiry because he feared the official determination to prove a crime. To the U.S. Consul in Gibraltar, Horatio Jones Sprague, Captain Winchester wrote from the safety of New York on March 10, 1873, that he had quit the colony after being convinced by a friend there that the judge and Attorney-General intended arresting him for hiring the crew to murder their officers.