A Chinese experimental electric car flew out of the third floor of its skyscraper headquarters in Shanghai, killing two test drivers.
Carmaker, Nio said a member of staff and a person from a partner company died after the ET5 model fell from the testing facility.
The shocking incident took place on Wednesday, June 22, at 5.20pm and the Tesla rival has launched an immediate investigation along with government officials.
Authorities attended the scene but were unable to save the two people inside the car.
One employee told Xin Huanghe: 'It's not a braking problem, (the driver) had hoped to put it in reverse gear, but instead put it in forward gear.'
Nio said: 'Our company has collaborated with public security department to launch the investigation and analysis of the cause of the accident. Based on the analysis of the situation at the scene, we can initially confirm that this was an accident not caused by the vehicle.'
'We feel very sad about this accident and would like to express our deepest condolences to our colleague and partner employee who lost their lives. A team has been set up to help the families.'