According to Jalopnik, a Tesla driver told the first responders at the scene that the car's Full Self-Driving (FSD) beta software braked unexpectedly, which caused a multi-car pileup in the San Francisco Bay area on Thanksgiving day. Nine people had mild injuries as a result of the incident.
Since then, the California Highway Patrol (CHP) has come forward with more details, as reported by ABC7. Some of the details came from amateur various videos of the event, which we've shared as part of the newscasts above.