Electric car-maker Tesla has been admonished by the US watchdog investigating a recent fatal crash involving one of its cars. The National Transportation Safety Board said it was "unhappy" the firm had made public details of the probe. The company had blogged on Friday that the Model X car involved's Autopilot self-steering system was in use at the time of the accident. Walter Huang, an Apple engineer, died after his car hit a barrier. Tesla had also revealed that logs from the vehicle's computer had indicated that the 38-year-old's hands were not on the steering wheel in the six seconds prior to the collision on California's Route 101.