He was born into a noble family, but the political and economic difficulties faced by the island as a colony of the Spanish Empire during the regional independence wars against the metropole meant that his household was poor.

He had previous links to land-based criminal activities, but the reason for Cofresí's change of vocation is unknown; historians speculate that he may have worked as a privateer aboard El Scipión, a ship owned by one of his cousins.

Cofresí proved too much for local authorities, who accepted international help to capture the pirate; Spain created an alliance with the West Indies Squadron and the Danish government of Saint Thomas.

[3] The theory was later discarded when their research uncovered a complete family tree prepared by Cofresí's cousin, Luigi de Jenner,[4] indicating that their name was spelled Kupferschein (not Kupferstein).

[9] According to Acosta, Cofresí's father Francesco Giuseppe Fortunato von Kupferschein received a lateinschule education and left at age 19 for Frankfurt (probably in search of a university or legal practice).

[60] However, Cofresí's associates Juan "El Indio" de los Reyes, Francisco Ramos and José "Pepe" Cartagena were released only months before his recorded reappearance.

[66] El Scipión employed questionable tactics later associated with the pirate, such as flying the flag of Gran Colombia so other ships would lower their guard (as she did in capturing the British frigate Aurora and the American brigantine Otter).

[69] In Orígenes portorriqueños Ramírez Brau speculates that Cofresí's time aboard El Scipión, or seeing a family member become a privateer, may have influenced his decision to become a pirate[33] after the crew's pay was threatened by the lawsuit.

Cofresí began his new career in early 1823, filling a role vacant in the Spanish Main since the death of Jean Lafitte, and was the last major target of West Indies anti-piracy operations.

[76] Cardona Bonet's research suggests that Cofresí organized improvised markets in Cabo Rojo, where plunder would be informally sold;[77] according to this theory, merchant families would buy goods for resale to the public.

[78] On October 28, 1823, months after the El Scipión case was settled, Cofresí attacked a ship registered to the harbor of Patillas[79] and robbed the small fishing boat of 800 pesos in cash.

[82] The central government, frustrated with Cabo Rojo's inefficiency, demanded the pirates' capture[83] and western Puerto Rico military commander José Rivas was ordered to exert pressure on local authorities.

[83] Although Cofresí was tracked to the beach in Peñones, near his brothers' homes in Guaniquilla, the operation only recovered the John's sails, meat, flour, cheese, lard, butter and candles;[83] the pirates escaped aboard a schooner.

By this time, joint governmental efforts had eradicated rampant buccaneering by Anglo-French seamen (primarily based on Jamaica and Tortuga), which had turned the Caribbean into a haven for pirates attacking shipments from the region's Spanish colonies; this made his capture a priority.

[86] The Salem Gazette reported that the following month a schooner sailed from Santo Domingo to Saona, capturing 18 pirates (including Manuel Reyes Paz) and a "considerable quantity" of leather, coffee, indigo, and cash.

[98] Aware that the problem had developed international overtones, Spanish-appointed governor of Puerto Rico Lt. Gen. Miguel Luciano de la Torre y Pando (1822–1837) made Cofresí's capture a priority.

[100] On January 23, 1824, de la Torre implemented anti-piracy measures in response to Spanish losses and political pressure from the United States,[101][102] ordering that pirates be tried in a military tribunal with the defendants considered enemy combatants.

[122] Poorly supplied after his hasty retreat, Cofresí docked at Jobos Bay on June 2, 1824;[122] about a dozen pirates invaded the hacienda of Francisco Antonio Ortiz, stealing his cattle.

[131] Madrona assembled troops and left for Cabo Rojo, launching an operation on June 17 which ended with the arrest of pirate Eustaquio Ventura de Luciano at the home of Juan Francisco.

[102] According to historian Enrique Ramírez Brau, an expedition weeks later by Fajardo commander Ramón Aboy to search Vieques, Culebra and the Windward Islands for pirates was actually after Cofresí.

[162] The group avoided capture by hiding in Ceiba, Fajardo, Naguabo, Jobos Bay and Vieques,[160] and when Cofresí sailed the east coast he reportedly flew the flag of Gran Colombia.

[163] On October 26 the USS Beagle, commanded by Charles T. Platt, navigated by John Low and carrying shopkeeper George Bedford (with a list of plundered goods, which were reportedly near Naguabo) left Saint Thomas.

[165] Commodore Porter's reaction to what was later known as the Fajardo Affair led to a diplomatic crisis which threatened war between Spain and the United States; Campos was later found to be involved in the distribution of loot.

[182] At the same time, de la Torre pressured the regional military commanders to take action against the pirates and undercover agents monitored maritime traffic in most coastal towns.

All four of Cofresí's victims left port shortly after the authorization on March 4; the task force was made up of Grampus, San José y Las Animas, an unidentified vessel belonging to Pierety and a third sloop staffed by volunteers from a Colombian frigate.

Cofresí was reportedly tried as an insurgent corsair (and listed as such in a subsequent explanatory action in Spain),[197] in accordance with measures enacted by governor Miguel de la Torre the year before.

[101] It is thought that the reason for the irregularities was that the Spanish government was under international scrutiny, with several neutral countries filing complaints about pirate and privateer attacks in Puerto Rican waters;[197] there was additional pressure due to the start of David Porter's court-martial in the United States for invading the municipality of Fajardo.

[197] The other pirates on trial were Manuel Aponte Monteverde of Añasco; Vicente del Valle Carbajal of Punta Espada (or Santo Domingo, depending on the report);[200] Vicente Ximénes of Cumaná; Antonio Delgado of Humacao; Victoriano Saldaña of Juncos; Agustín de Soto of San Germán; Carlos Díaz of Trinidad de Barlovento; Carlos Torres of Fajardo; Juan Manuel Fuentes of Havana, and José Rodríguez of Curaçao.

[56] A letter from Sloat to United States Secretary of the Navy Samuel L. Southard implied that at least some of the pirates were intended to be "beheaded and quartered, and their parts sent to all the small ports around the island to be exhibited".

These apologetics attempt to justify his piracy, blaming it on poverty, revenge or a desire to restore his family's honor,[229] and portray Cofresí as a class hero defying official inequality and corruption.