Historian Ander Berrojalbiz (Durango, 1983) has published a work compiling short articles on various topics, notably providing new verified data on witchcraft and heresy in the Basque lands. Among his most significant findings, Berrojalbiz re-establishes the origin of the 1507 witch hunt in Oñati, rather than Durango as previously thought, offering a new interpretation of the judicial processes that marked those turbulent years.

One of the first articles in his book is dedicated to the often-cited burning of over 30 women for witchcraft in 1507. Berrojalbiz explains that while this event has been present in history books, its exact location was unknown. It was erroneously speculated to be in Navarra, then Durango, due to the Inquisition's presence there in 1508 and 1509. However, new sources now indicate it occurred in Oñati and that the processes were carried out by local authorities, the civil justice system.

The documentation uncovered by Berrojalbiz, starting in 2016, suggested the burning took place in Gipuzkoa, indirectly pointing to the County of Oñati. An appeal concerning a jurisdictional conflict between the County and the Diocese of Calahorra has corroborated this. This appeal contains a document dated November 7, 1507, stating that Oñati's local justice had already conducted trials against “witches or sorgiñas.” The Inquisition did not intervene until 1508, and by May of that year, it was established in Durango.

The historian highlights key differences between the trials in Oñati and those in Durango under the Holy Inquisition. The Oñati processes, being civil justice, likely focused on alleged magical harm to the community, such as crop losses or plagues. The Inquisition, conversely, sought confessions of pacts with the devil and renunciation of Christian faith through torture, thereby asserting its ecclesiastical jurisdiction. The 1508-1509 Inquisition, according to Berrojalbiz, was one of the least protective of rights in the history of the Spanish Holy Office regarding witchcraft cases.

The book also details the case of María San Juan de Garonda, a midwife from Mungia. Although her trial was conducted by the Inquisition, she was arrested by authorities from the Lordship of Bizkaia in early 1508. Her mother had also been burned for witchcraft thirty years prior. Despite torture, María San Juan did not confess, but was still condemned to the stake after a form of “popular jury.” Her sentence was read at an auto-da-fé held on November 16, 1508.