A teenage victim of the Asiana Airlines crash in San Francisco was killed when she was struck by a vehicle at the scene, a coroner said.
Mr Foucrault said the 16-year-old died of multiple blunt injuries consistent with being run over by a motor vehicle. He did not say what that vehicle was.
San Francisco fire chief Joanne Hayes-White said officials believe the girl was struck by a specialised fire vehicle.
Authorities confirmed last week that Yuan was hit by a vehicle racing to extinguish flames which broke out on the Boeing 777.
Police said she was on the ground and covered in fire-retardant foam that rescuers had sprayed on the wreckage.
"It's very difficult and devastating news for all of us," Ms Hayes-White said.
Yuan and her middle school classmate, 16-year-old Wang Linjia, died on July 6 at San Francisco International Airport. The other victim, 15-year-old Liu Yipeng, died in hospital on July 12. Dozens of other people were injured.
Yuan and Linjia were students at Jiangshan Middle School in Zhejiang, an affluent coastal province in eastern China, Chinese state media has reported. They were part of a group of students and teachers from the school who were heading to summer camp in southern California. Yuan and Linjia were seated at the back of the plane, federal investigators have said.
Meanwhile, the probe into the crash itself continues. Investigators have said the plane came in too low and too slow, clipping its landing gear and then its tail on a rocky seawall just short of the runway.