Antonio “El Gaucho" Rivero was a gaucho who murdered the five leading members of the settlement of Port Louis on the Falkland Islands on 26 August 1833.
Rivero was born in Concepción del Uruguay, at that time a rural village in Entre Ríos Province, Viceroyalty of the Río de la Plata, now part of Argentina on November 27, 1808.
When he was about 20 years old, he was taken to the Falkland Islands by Luis Vernet, to work as a gaucho. Conditions of employment caused discontent among Vernet's workers. They were paid with promissory notes which Matthew Brisbane, Vernet's deputy, devalued following the reduction in Vernet's fortunes. On 26 August 1833, five Indian convicts and three gauchos led by Rivero embarked on a killing spree which resulted in the deaths of Brisbane and the senior leaders of the settlement. Thomas Helsby, a clerk in the employ of Vernet, wrote an account of the murders.
At around ten in the morning, Helsby departed Brisbane's house to buy some oil from William Dickson, whom he found at the house of Antonio Wagner. Other people there included Daniel McKay and Joseph Douglas. On leaving, as he passed the house of Santiago Lopez, Helsby encountered the murderers. The gang was led by Rivero and comprised the gauchos José María Luna, Juan Brasido and the five Charrúa Indians Manuel Gonzales, Luciano Flores, Manuel Godoy, Felipe Salagar and Lattorre. They were armed with "muskets, pistols, swords, dirks and knives".
Alarmed, Helsby ran to Brisbane's house for aid, but he found it locked and could raise no response. He was informed by other residents that Brisbane had been killed, along with Juan Simon (the Capitan of the Gauchos). A third man, Don Ventura, had been left for dead, wounded in the throat by a musket, his head split and his hand almost severed by a sword, but he had since escaped by a back window and headed toward the house of Antonina Roxa. Helsby then heard two musket shots from the house of Antonio Wagner: Wagner and Dickson had been killed, witnessed by Joseph Douglas and Daniel McKay.