While on board the Felicidade, a second ship named the Echo was spotted, and both the Wasp and the Felicidade gave chase - though the Wasp was quickly left behind. After a pursuit lasting 3 days, the Echo surrendered. The captain of the Echo and its crew of twenty one were taken on board the Felicidade, which was put under the command of a sailor named Midshipman Palmer with nine sailors, while Lieutenant Stupart and a boarding party of seven manned the Echo. That night, however, as Palmer apparently 'permitted himself the luxury of a bath', the captured Brazilian crew rose up, killed the ten British sailors and threw their bodies overboard, before fleeing once more.
The Echo was unable to follow, but three days later the Felicidade was again stopped by another British ship. The crew of this ship knew nothing about the previous events but became suspicious about the unexplained bloodstains on the deck and questioned the the captured men. Eventually two crew members confessed and the Brazilian crew were once more taken into custody. This time they were taken to England where they were tried at Exeter Assizes at the end of July 1845 for the murder of the ten British seamen.
It was accepted law that English courts had jurisdiction over offences committed on British ships at sea, irrespective of the nationality of the offender. However, it also followed from this that they had no jurisdiction over offences committed on foreign vessels. The case accordingly turned on the question of the nationality of the Felicidade at the time of the incident, for if it were accepted that it was a foreign ship then the crew would have a right to resist using force, for the British sailors would then be acting without lawful authority and could legally be viewed as pirates. For the Crown it was contended that the sailors had acted lawfully under treaties in force between Britain and Brazil for the suppression of the slave trade. Under these treaties it was argued that ships could lawfully be detained either where there were slaves on board or where there was equipment supporting slavery. Accordingly it was argued that the Felicidade in effect became British at the moment of its capture and was operating under British authority. The lawyers for the defence argued that while the original apprehension of the Echo might have been legal under the treaty, there was no jurisdiction in respect of a different crime committed on board a Brazilian ship which they argued had been illegally seized by the Wasp. The majority of the court agreed with this view and the crew of the Echo were set at liberty and returned to Brazil at the expense of the British government.
This is in many ways a surprising decision. It might have been expected that the English Courts would jump to the protection of British sailors who, whatever their precise legal status, were acting in good faith and seeking to suppress the illegal Brazilian slave trade- a project that was actively supported by the government of the time. It might also have been expected that, in the era of Lord Palmerston's 'gunboat diplomacy', the courts would protect British sailors from being murdered. What emerges instead is that the courts upheld (albeit only by a majority) a highly technical reading of the jurisdiction of the courts, which seemed to cut against the political interests of the British state.