In contrast, local police previously said witness statements suggested there was nobody in the driver's seat when the car crashed into a tree and killed the two occupants.

Tesla shares rose on the disclosure and were recently up 3.1% to $892.70.

The NTSB said a review of vehicle data indicates "both the driver and the passenger seats were occupied, and that the seat belts were buckled when the (event data recorder) recorded the crash."

Based on a forensic examination of the steering wheel and information from the car's event data recorder, the vehicle reached a speed of 67 mph during the 5 seconds leading up to the crash, NTSB added.

The NTSB also said data indicates "the driver was applying the accelerator in the time leading up to the crash; application of the accelerator pedal was found to be as high as 98.8%."

Tesla did not immediately respond to a request for comment.

The crash raised new alarms about Tesla's driver assistance system Autopilot in April after Harris County Constable Mark Herman said "We have witness statements from people that said they left to test drive the vehicle without a driver and to show the friend how it can drive itself."

Herman's office did not immediately comment Thursday.

The National Highway Traffic Safety Administration, which is also investigating the crash, declined to comment.

The NTSB said that "no conclusions about how the crash happened should be drawn from the information in this investigative update" and all aspects of the crash remain under investigation.

The NTSB said its Recorders Laboratory repaired the car's event data recorder and extracted critical precrash information from the unit.

The NTSB said in May that testing suggested the vehicle's automated steering system was "not available" on the road where the accident occurred.

Last month, an autopsy report showed one of the two victims had a blood-alcohol level that exceeded the legal driving limit. The car was destroyed by a post-crash fire and the victims badly burned.

(Reporting by David Shepardson; Editing by Nick Macfie and Chizu Nomiyama)

By David Shepardson