SAN FRANCISCO, CA - JULY 06: A fire truck stands in front of the closed international terminal at San Francisco International Airport July 6, 2013 in San Francisco, California. A Boeing 777 Asiana Airlines passenger aircraft coming from Seoul, South Korea crashed while landing. There has been no official confirmation of casualties. (Photo by Sarah Rice/Getty Images) A fire truck stands in front of the closed international terminal at San Francisco International Airport July 6, 2013. (Photo by Sarah Rice/Getty Images)

SAN FRANCISCO (CBS/AP) — Amid the marvel of nearly all aboard Asiana Flight 214 surviving a crash landing, authorities continue investigating an unspeakable tragedy that may have unfolded during the frantic rescue – whether a teenage girl made it out of the plane only to be run over by a rescue vehicle.

The San Francisco Police Dept. said Tuesday that the SFPD’s hit-and-run unit has now taken over investigating the death of a 16-year-old Chinese girl who might have been killed accidentally on the runway Saturday by a fire truck racing to the scene.

“An investigation is underway, and that’s all I can say,” police spokesman Albie Esparza said.

The department noted its hit-and-run unit and major accidents investigations team both would typically be involved in any such investigations.

The girl and a classmate comprised the crash’s two fatalities. Federal and local officials on Monday addressed the possibility that she might have been killed as the first firefighters responded to the wrecked, smoking airliner.

“One of our fire apparatus may have come into contact with one of our two victims,” San Francisco Fire Chief Joanne Hayes-White said during a news conference called to highlight the heroic efforts of first responders. “I assure you, we are looking closely at this.”

Findings of what caused the 16-year-old’s death – the plane crash, the fire truck, or both – might not come for several weeks.

A firefighter first reported to a superior Saturday that a passenger who was on the ground roughly 30 feet from the wreckage and near the escape slide may have been run over as fire crews were shifting from dousing the flames to taking victims to hospitals, officials said.

Police, FBI agents, the coroner and other officials were notified after the firefighter at the scene reported his concerns, officials said. The drivers of the first five trucks to respond to the emergency were given drug and alcohol tests, which they passed.

It’s not clear why the firefighters thought someone had been run over. Fire Department officials said they did not want to provide details because of the ongoing investigation by city police, the county coroner whose office received the body and the National Transportation Safety Board.

Airport video surveillance footage reviewed by federal accident investigators proved inconclusive, NTSB Chairwoman Deborah Hersman said.

“It is a very serious issue and we want to understand it,” she said. “We want to make sure we have all the facts before we reach conclusions.”

The job of gathering those facts – including determining whether the evidence shows that the girl was hit by the truck and if she was still alive when it happened – has fallen in large part to San Mateo County Coroner Robert Foucrault.

He said Monday that the two Chinese girls had been identified through fingerprints. Their autopsies were completed and their bodies prepared to be claimed by their parents, who were expected to arrive in San Francisco soon.

Foucrault originally had planned to release a preliminary cause of death for each of them on Monday. But he decided to wait until he could do a broader inquiry that will include reviewing written information from the public safety agencies that responded to the crash, audio dispatch files and perhaps interviews.

“This is a very high-profile case and has obviously generated a lot of attention,” Foucrault said at his office located a few miles south of San Francisco International Airport where the plane crashed Saturday. “I want to make absolutely sure my conclusions are correct.”

He said he made the decision to hold off independently and that neither city officials nor federal accident investigators had asked him for a postponement.

Chinese state media and Asiana 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 a summer camps in Southern California, according to education authorities in China.

(Copyright 2013 CBS San Francisco. All rights reserved.)