Florida Highway Patrol says DVD player found in the car.

The driver of a Tesla Model S who was killed when his car’s Autopilot system didn’t brake before hitting a semi truck may have been watching a movie while driving, alleges the driver of the truck.

The truck driver involved in the accident, Frank Baressi, told the Associated Press that the Tesla driver was watching Harry Potter at the time of the crash. A sergeant with the Florida Highway Patrol, meanwhile, told Reuters that, “There was a portable DVD player in the vehicle.” Neither report has been officially confirmed as the cause of the accident.

Joshua Brown, aged 40, was killed earlier this year when his Tesla Model S drove under a semi truck trailer that was crossing the roadway in Florida. In a blog post about the incident, Tesla Motors said that the car’s Autopilot semi-autonomous driving system was engaged, but the camera couldn’t detect the white trailer against the bright sky; neither the system nor Brown braked before the crash. The National Highway Traffic Safety Administration has launched a preliminary investigation into the accident to determine “the design and performance of any automated driving systems in use at the time of the crash.”

Tesla has reiterated that Autopilot is intended as a driving aid, rather than a fully autonomous system, and that the in-car display advises the driver, “Always keep your hands on the wheel. Be prepared to take over at any time.” The company described Autopilot as “still in a public beta phase” and said that “Autopilot is getting better all the time, but it is not perfect and still requires the driver to remain alert.”

Sources: Associated Press, Reuters

Gallery: Tesla Autopilot