Operation Bergon

Operation Bergon was a joint law enforcement operation conducted on December 16, 2021, by US Immigration and Customs Enforcement Homeland Security Investigations (ICE HSI) and the Brazilian Ministry of Justice and Public Security (MJSP), targeting neo-Nazi cells operating on US-based online platforms and planning mass casualty attacks against Jewish and Black civilians, schools, and critical infrastructure in Brazil. The operation resulted in 31 search warrants executed simultaneously across seven Brazilian states and four arrests, with homemade explosives, weapons, and attack planning materials seized.¹

Investigation Background

The investigation originated in May 2021 when ICE HSI identified criminal neo-Nazi groups using US-based online platforms to coordinate violence and recruit members in Brazil. Between May and November 2021, HSI passed a series of investigative leads to the MJSP Secretariat for Integrated Operations' Cyber Laboratory. The Cyber Laboratory coordinated with state police and prosecutors' offices across the seven affected states (Rio de Janeiro, Minas Gerais, Sao Paulo, Parana, Santa Catarina, Rio Grande do Sul, and Rio Grande do Norte) in advance of the simultaneous December 16 execution of warrants.¹

The December 2021 Operation

On December 16, 2021, Brazilian state police and prosecutors across seven states executed 31 search warrants and four arrest warrants. Evidence seized included homemade explosives, conventional weapons, Nazi paraphernalia, and detailed plans for future attacks. One named suspect, identified publicly as Matheus Hades NS, a 43-year-old security guard from Campinas, Sao Paulo, was alleged to have attempted to recruit young people to bomb the Angra dos Reis nuclear power plant, located in the Rio de Janeiro state coastal area. Matheus Hades NS reportedly stated his intent to "kill and then commit suicide." Other individuals in the cells were planning attacks against public areas including schools, as well as hate crimes against Jewish and Black civilians. One perpetrator intended to use explosives at a New Year's Eve celebration in Sao Paulo state.¹²

US-Brazil Cooperation Framework

Operation Bergon is the most documented instance of pre-2022 US-Brazil law enforcement cooperation specifically targeting neo-Nazi accelerationist networks, predating the wave of Brazilian school attacks that began with the 2022 Aracruz School Shootings by approximately eleven months. The ICE HSI role was to identify online activity on US-hosted platforms and pass leads to Brazilian counterparts; the arrest and search warrant execution authority remained with Brazilian state and federal agencies. The operational model, in which HSI served as an intelligence-sharing partner rather than a direct enforcement actor, mirrors the framework ICE HSI has used in similar operations in other Latin American countries.¹

No public record of prosecution outcomes for the four arrested individuals has appeared in English-language sources as of mid-2026. Whether Matheus Hades NS was formally charged and tried in Brazilian courts is not established in the public record.