Tesla is already under investigation in the US for what was believed to be the first reported fatality in a Model S that occurred while the sedan's cruise control feature, called Autopilot, was engaged. That accident happened in May.
However, reports says, Autopilot may have been involved in an earlier fatal accident in China.
In January 2016, a man borrowed a Model S from his father and was driving on Hong Kong-Macau Expressway, according to Chinese media reports on Wednesday. The driver reportedly crashed into a street cleaning truck that occupied half of his lane and was killed in the accident.
The impact destroyed the vehicle's logs, which are needed to determine if Autopilot was being used at the time. Traffic police reportedly said there were no brake marks, and dashcam video appears to show the Model S crashing into the truck at a high speed.
Tesla's owner manual has a warning against this kind of rear-end situations:
"Traffic-Aware Cruise Control can not detect all objects and may not brake/decelerate for stationary vehicles, especially in situations when you are driving over 50 mph (80 km/h) and a vehicle you are following moves out of your driving path and a stationary vehicle or object, bicycle, or pedestrian is in front of you instead," it reads.
The family of the driver is now suing Tesla, according to reports, and the incident is still under investigation by the local authorities.
In response to CNET's request for comment, Tesla offered this statement:
We were saddened to learn of the death of our customer's son. We take any incident with our vehicles very seriously and immediately reached out to our customer when we learned of the crash. Because of the damage caused by the collision, the car was physically incapable of transmitting log data to our servers and we therefore have no way of knowing whether or not Autopilot was engaged at the time of the crash. We have tried repeatedly to work with our customer to investigate the cause of the crash, but he has not provided us with any additional information that would allow us to do so.
This week, Tesla said it's going to upgrade its software to version 8 that, among other improvements, will make Autopilot smarter.
Updated at 12:58 p.m. PT: with a comment from Tesla.