The Briefing:
- A Mendoza tribunal sentenced former nun Kumiko Kosaka to 20 years in prison on September 24, 2026, for the sexual abuse of deaf students at the Próvolo Institute — two years after the same allegations had ended in acquittal.
- She will remain free while her lawyers appeal, but must surrender her passport, stay inside Mendoza province, and post bail of roughly 15 million pesos.
- The reversal traces back to an August 2026 provincial Supreme Court ruling that found the original acquittal had weighed the evidence in isolated fragments rather than as a whole.
A Mendoza criminal court handed down a 20-year prison sentence against former nun Kumiko Kosaka on Thursday, September 24, 2026, closing — at least for now — one of the darkest chapters in the Catholic Church's worst abuse scandal in Argentina. The Japanese-born religious sister was found responsible for seven separate acts of sexual abuse against five students at the former Antonio Próvolo Institute, a boarding school for deaf children in Luján de Cuyo, Mendoza province.
The Sentence: Seven Counts, Five Victims
Judges Gabriel Bragagnolo, Federico Martínez and Juan Manuel Pina González read the verdict inside Courtroom 15 of Mendoza's judicial complex, ruling that Kosaka acted as an accomplice in three of the abuse cases and as the direct perpetrator in the remaining four, according to prosecutor Alejandro Iturbide's own account of the ruling. That total of seven acts marks an expansion beyond the five episodes a higher court had already attributed to her weeks earlier — prosecutors and plaintiff attorneys had pushed for 22 years, and judges landed two years short of that figure, crediting the more than five years Kosaka had already spent in pretrial detention. Alongside the prison term, the court barred her for a decade — the maximum the law allows — from any work involving the care, custody or education of minors.
How an Acquittal Became a Conviction
None of this would have happened without an unusual legal turn. Back in October 2023, the same criminal tribunal that would later convict Kosaka had instead cleared her of every charge, following two years of hearings, testimony from more than 100 witnesses and roughly 300 court sessions. Victims' families reacted with outrage, and prosecutors appealed. On August 21, 2026, Mendoza's provincial Supreme Court overturned that acquittal in a split 2-1 decision, with judge Teresa Day writing the lead opinion, substitute judge Silvina Miquel concurring, and judge Julio Gómez dissenting in favor of upholding the original not-guilty finding. The high court's roughly 300-page ruling concluded the first trial had evaluated the evidence "in fragments," never weighing the case file as a whole — a finding that cleared the way for a fresh sentencing hearing that ultimately expanded the case from five acts to seven.
'A Repair for a Very Grave Harm'
Iturbide didn't hide his relief as he left the courtroom. He told reporters the ruling brought "much satisfaction" to prosecutors and that it amounts to "a repair for a very grave harm" done to the victims in the case. To keep Kosaka within reach of the courts while her sentence works through the appeals process, judges set bail at 15 million pesos and ordered her to establish residence in Mendoza and hand over her passport immediately — a notable condition, given that the nun had reportedly been living in Buenos Aires. Defense attorneys Carlos Varela Álvarez and Enoc Ortiz maintained her innocence throughout the sentencing hearing and have already signaled they will challenge the ruling before Mendoza's provincial Supreme Court and, if necessary, the national Supreme Court.
Decades of Abuse Behind Institute Walls
The investigation into the Próvolo Institute exposed a pattern of abuse that ran from 2005 to 2016 and affected more than 20 hearing-impaired students. The case entered public view on November 18, 2016, when sign-language teacher Luis Batistelli — assisted by an interpreter at a legislative event in Mendoza — described what was happening inside the institution. A week later, prosecutors raided the school. By November 2019, a Mendoza tribunal had sentenced Italian priest Nicola Corradi to 42 years and Argentine priest Horacio Corbacho to 45 years — among the toughest penalties an Argentine court has imposed on a Catholic clergyman for crimes of this kind — while gardener Armando Gómez Bravo received 18 years. Argentina's national Supreme Court has since let Corbacho's sentence stand.
The scandal reached far beyond Argentina's borders. In Italy, 67 former students came forward describing abuse at the institute's original Verona campus reportedly dating back to the 1950s, suggesting the pattern of abuse stretched across more than seven decades and three countries. Pope Francis never addressed the accusations publicly, though he ordered a preliminary Vatican investigation into the Institute in 2017, roughly a year after the Argentine priests' arrests.
What's Next for Kosaka
The open question isn't whether Kosaka was convicted — she was — but when, if ever, she will actually serve the sentence. Beyond the time already credited for pretrial detention, she remains free on bail while her defense pursues appeals through both the provincial and national high courts, a process that could stretch on for months or longer. For victims and their families, who have waited nearly a decade for a verdict, September 24 marked real progress — even if the legal fight is far from over.
