On June 19, a Tesla Model 3 drove through the front wall of a house in Katy, Texas, a suburb of Houston, and killed 76-year-old Martha Avila, who was inside. The driver, 44-year-old Michael Butler, told authorities he had been using Tesla's assisted-driving feature and then passed out. That account, it turns out, does not hold up.
The National Transportation Safety Board, the independent U.S. body that investigates transport accidents, released preliminary findings confirming that Butler pressed the accelerator pedal to 100 percent. That action immediately disabled the assisted-driving system and gave Butler full manual control of the car. The vehicle reached 73 mph on a residential street posted at 30 mph. Butler never touched the brakes.
Investigators also found no sign of a medical emergency. No alcohol, no drugs, no seizure, no stroke, no heart attack. What they did find was a search history on his phone: in the weeks before the crash, Butler had searched terms including "Tesla FSD not aggressive enough 2026" and "Tesla FSD too timid." Prosecutors are using those searches to argue the acceleration was deliberate, not accidental. Butler has been charged with manslaughter, which in Texas carries two to 20 years in prison.
The victim's family has filed a civil lawsuit against both Butler and Tesla, seeking damages for her death. That civil case is separate from the criminal charge, and both are still pending.
Here is where it gets more complicated for Tesla. This case clears the assisted-driving software of direct blame. But U.S. safety regulators at the National Highway Traffic Safety Administration (NHTSA) have a separate, broader investigation running at the same time, covering roughly 3.2 million Tesla vehicles equipped with the same general class of software. That investigation has been escalated to an "engineering analysis," which is the last formal step before regulators can force a recall. The focus there is different: it is examining whether Tesla's system fails to warn drivers quickly enough when cameras cannot read the road properly, such as in glare or fog.
Since 2016, federal regulators have opened nearly 50 special crash investigations involving Tesla's driver-assistance systems, with about two dozen deaths reported across those cases. In 2025, a Florida jury handed down a $243 million verdict against Tesla in a different FSD-related crash, finding the company 33 percent responsible even though the driver was clearly misusing the system. That verdict matters because it established that a driver being at fault and a manufacturer being civilly liable are not mutually exclusive.
This is the tension that sits at the center of every case involving this category of software. The system is marketed with the name "Full Self-Driving," it handles steering and navigation, and many drivers treat it as more capable than it is. Tesla legally requires drivers to stay alert and ready to take over at any moment. But the gap between what the name suggests and what the system actually does is wide, and courts are increasingly treating that gap as a design and marketing question, not just a driver behavior question.
For now, Butler appears to bear the primary legal responsibility for what happened in Katy. The NTSB's preliminary findings say the car behaved as designed: it stopped driving itself the moment the driver overrode it. The investigation is ongoing and conclusions may change. What will not change is the regulatory pressure building around this category of technology more broadly, and the precedent that drivers cannot simply point to software when something goes wrong.