Man Convicted of Dangerous Transbay Fire

San Francisco District Attorney Brooke Jenkins said on May 21 that a jury convicted Viengphet Sasone, 48, of possession of an incendiary device after a fire inside the Transbay Terminal. Prosecutors said the fire was set before dawn on December 13, 2025, in the Muni plaza area of the downtown transit hub. A Transbay security guard spotted Sasone near the fire, according to the district attorney’s office. Another guard used an extinguisher to put it out before it spread, prosecutors said. ### Who was convicted, and of what charge? Viengphet Sasone was convicted of possession of an incendiary device under California Penal Code 453(a), the San Francisco District Attorney’s Office said in a May 21 release. The conviction followed a jury trial in San Francisco Superior Court, according to the same release. Brooke Jenkins said in the release that Sasone’s conduct was “incredibly dangerous” and said the fire could have caused significant damage to the terminal and disrupted passengers without the intervention of security staff. Assistant District Attorney Kirk Earl prosecuted the case, the office said. (sfdistrictattorney.org) ### Where inside the terminal did prosecutors say the fire was set? Prosecutors said the fire was started under an escalator in the Muni plaza of the Transbay Terminal in San Francisco at about 4:30 a.m. on December 13, 2025. The district attorney’s office said Sasone set bedding on fire on top of a garbage can. (sfdistrictattorney.org) The Transbay Terminal, also known as the Salesforce Transit Center complex, is one of San Francisco’s main transit facilities, serving buses and connections in the downtown area. Prosecutors did not report major structural damage in their release, and they said the fire was extinguished while still small. (sfdistrictattorney.org) ### How was the fire stopped before it spread? A Transbay security guard saw Sasone by the fire and alerted a colleague, the district attorney’s office said. That colleague put out the blaze with a fire extinguisher before it grew larger, according to prosecutors. Jenkins thanked Transbay staff for what she called their quick work and partnership with law enforcement. (sfdistrictattorney.org) Earl said in the release that “any fire in public has the potential to cause serious harm,” even though this one was still small when it was extinguished. ### What did police say they found when they arrived? (sfdistrictattorney.org) San Francisco police officers arrived at the scene and arrested Sasone, according to the district attorney’s office. Prosecutors said he was in possession of an orange lighter when officers took him into custody. The district attorney’s office said its case relied on the San Francisco Police Department’s investigation, along with testimony and evidence presented at trial. (sfdistrictattorney.org) The office also named paralegal Raquel Paz Aleman and IT staff Ada Yu and Leland Chan in the prosecution team. ### What comes next in the case? (sfdistrictattorney.org) The district attorney’s release identified the matter as Court Number 25027264. The office did not include a sentencing date in the release published May 21. Any next hearing or sentencing date would be expected to appear in San Francisco Superior Court records under that case number. (sfdistrictattorney.org) For now, the public account from prosecutors ends with the jury’s guilty verdict and the conviction announcement issued Thursday.