Killing of Nguyễn Xuân Đạt

On July 26, 2025, eleven videos and ninety-eight images of what became known as The Vietnamese Butcher began circulating on Telegram and other encrypted messaging apps. According to the earliest reports, as early as February 2025, the videos and images were being sold as a pack on the dark web and the Chinese platform Baidu Tieba. although this has not been corroborated or verified by police. Prior to the recorded killing, another longer video had shown a rehearsal between the two persons, where the assailant is shown wearing a Guy Fawkes mask, and only grazing the person's neck with his cleaver, before embracing the person at the end of the video. == Investigations ==

Online investigation Before an official investigation, many Vietnamese investigators used open-source intelligence (OSINT) methods to gain more information about the case. It was deduced that both people were speaking regional Vietnamese accents, and from floor tiles and household items in the initial video they concluded that the place of the killing was either near the China–Vietnam border or the Cambodia–Vietnam border. Initial suspicions towards a Buddhist who was claimed to have interacted with the victim were dropped after they had denied involvement. According to his neighbors, Đạt was raised in Hanoi by his relatives due to his mother's mental illness, and worked as a laborer and fishmonger in Hà Đông, Hanoi. On November 23, an 88-page summary, often referred to as "the 88-page document" (), which had documented information about the case, was published on OCIV. The document contained theories and information about Đạt and analysis of the crime scene. It held Sáng to be responsible, because of the correlations between the assailant and Sáng's bodily characteristics, and their shared activities as well as both of their contact with each other. A longer, updated version which had 110 pages, appeared on OCIV on November 27, and posited stronger correlations between the assailant and Sáng. Official investigation On October 3, 2025, an official notice from the Ministry of Public Security informed that an official investigation of the case began after their "observations of the online space". According to Sin Chew Daily, although the video had spread from the dark web to mainstream domestic platforms, the police only announced an investigation had begun after the release of the 88-page investigation. The same day, the Investigation Police Agency of Lạng Sơn Provincial Police issued a decision to convict a criminal case of murder. According to Sáng's confessions, he and Đạt had met through social media in 2020, and on January 25, 2025, after contact via mobile phone, Đạt had entered Sáng's workplace at the office of Market Surveillance Unit No. 4 (which had been vacant due to Tết celebrations) prior to the incident. The investigation is ongoing. == Media coverage ==

On August 21, 2025, Ben Ditto of Vice wrote in an article on The Vietnamese Butcher that, though the case had not yet drawn as much international attention as some others, "online sleuths" were already "working overtime to put names to the victim and the killer". with the media focusing on the crime-solving efforts in the form of open-source intelligence. Many news outlets emphasized the role of "cyber investigators" in shedding light on the case and said that the arrest of Sáng meant that the key details in the cyber investigation documents were accurate. Hong Kong's media outlet HK01 and Singapore's The Straits Times said that "online sleuths" played an important part in the identification of Sáng and the murder site, On December 10, 2025, police charged two individuals for spreading false information about the incident. == See also ==