 Manuel Moreno speculated later that he was poisoned by the captain . Manuel Moreno was unsure of whether the captain really given him that substance , or if he substituted something else , or gave an even higher dose . Circumstances did not allow an autopsy to be performed . Further points used to sustain the idea of a murder are the captain 's refusal to land elsewhere , his slow sailing , his administration of the emetic in secrecy , and that he didn 't return to Buenos Aires with the ship . Enrique de Gandía pointed to an irregular ruling of the Junta that appointed a British person named Curtis as Moreno 's replacement for the diplomatic mission in the case of Moreno 's death . The son of Mariano Moreno commented to the historian Adolfo Saldías that his mother , Guadalupe Cuenca , received an anonymous gift of a mourning hand fan and handkerchief , with instructions to use them soon . By that time , the murder of Moreno was a common assumption , and it was mentioned during the trial of residence of the members of the Junta . Juan Madera stated at the trial that Moreno may have requested to go to Britain because he was afraid of being murdered , and that he may have stated this during the meeting when the Junta discussed his resignation . Modern author Manuel Luis Martín studied the health of both Moreno and his family , and concluded that he died of natural causes . 
