SAN FRANCISCO (CBS/AP) -- Investigators have reviewed San Francisco International Airport surveillance video to determine whether an emergency vehicle ran over one of two teenage girls killed in Saturday's plane crash, but "it wasn't conclusive," a federal official said Monday.
National Transportation Safety Board chairwoman Deborah Hersman called the possibility a "very serious issue."
"I can tell you that the two fatalities were located in seats towards the rear of the aircraft. This is an area of the aircraft that was structurally significantly damaged. It's an area where we're seeing a lot of the critical or serious injuries," Hersman said of the girls' location.
Investigators want to make sure they have all the facts before reaching any conclusions, Hersman said at a news conference, adding that the coroner has not yet determined the girl's cause of death and is charged with doing so.
San Mateo County Coroner Robert Foucrault said his office was conducting an autopsy to determine whether the girl survived the crash but was run over and killed by a responding vehicle. Foucrault said his staff was "made aware of the possibility at the scene" by San Francisco Fire Department officials on Saturday.
The coroner said he hoped to have preliminary autopsy results later Monday, but would not release the results for "at least two or three weeks" until his full investigation is completed. Foucrault said he made that decision independently without consulting either city officials or federal accident investigators.
SFFD Chief Joanne Hayes-White and Assistant Deputy Chief Dale Carnes both publicly acknowledged earlier Monday that one of their trucks responding to the Asiana Airlines crash might have run over one of the victims.
"There was a possibility one of two fatalities might have been contacted by one of our apparatus at one point during the incident," Carnes said.
In addition to the coroner, Carnes said police, FBI and other officials were notified "immediately" after a firefighter at the scene reported his concerns.
"I assure you we are looking closely at this," Hayes-White said during a news conference held separate from the NTSB briefing. "That could have been something that happened in the chaos. It will be part of our investigation."
She added that the five drivers of rescue vehicles that day all passed drug and alcohol tests. No one has been suspended.
The body of the girl who might have been struck was found on the left side of the aircraft about 30 feet away from where the Boeing 777 came to rest after it skidded down the tarmac, said Foucrault.
The girl was not far from an emergency slide, he said. The other body was found on the runway near where the plane's tail broke off upon impact, he said. The coroner said both girls were pronounced dead at the airport.
The teenagers' families were expected to arrive in San Francisco sometime Monday, and they will receive the autopsy results long before they are made public, Foucrault said. He indicated positive identifications were made through fingerprints.
Chinese state media and Asiana Airlines have identified the girls as Ye Mengyuan and Wang Linjia, students at Jiangshan Middle School in Zhejiang, an affluent coastal province in eastern China. They were part of a group of 29 students and five teachers from the school who were heading to summer camps in California, according to education authorities in China.
While speaking to reporters at San Francisco General Hospital on Sunday, San Francisco Mayor Ed Lee called the questions being raised about a rescue vehicle possibly striking one of the victims "unsubstantiated."
"It was very, very hectic when they arrived minutes after the plane came to rest and there was smoke coming out, and people were trying to get out as quickly as they could," Lee said.
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