First responders say that no one was behind the wheel when a Tesla Model S crashed into a tree in Texas, killing the two men inside the vehicle. But Tesla founder Elon Musk is pushing back on the idea that the car was driverless—tweeting that his data shows the autopilot wasn’t engaged and that the owner had not purchased the “full self-driving” package. The National Highway Traffic Safety Association and the National Transportation Board are investigating the Saturday night crash in Spring, which ended with the Tesla bursting into flames. The victims have not yet been identified.