SAN FRANCISCO (AP) — Amid the marvel of nearly all aboard Asiana Flight 214 surviving a crash landing, authorities here are 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.

Federal and local officials on Monday addressed the possibility that the Chinese girl, who along with a classmate comprised the crash's two fatalities, might have been killed accidentally on the runway as the first firefighters raced to the scene of a wrecked, smoking airliner.

"One of our fire apparatus may have come into contact with one of our two victims," 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 — may not come for several weeks.

A firefighter first reported to a superior on 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 the two Chinese girls have 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 on Monday.

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.

Meanwhile, firefighters and police officers on Monday gave their first accounts of what they encountered in the first minutes after the Saturday's crash.

Most of the 307 people on board had exited the crippled craft before firefighters arrived, but four passengers were still trapped in the back.

Three firefighters and two police officers, who did not have safety gear, rushed onto the plane to help evacuate trapped passengers, including one who was trapped under a collapsed bulkhead. They had gotten everyone off the craft except one elderly man who was in his seat, moaning and unable to move.

"We were running out of time," San Francisco Fire Department Lt. Dave Monteverdi recalled. "The smoke was starting to get thicker and thicker. So we had no choice. We stood him up and amazingly, he started shuffling his feet. ... We were able to get him out and he was pretty much the last person off the plane."

Monteverdi and his two colleagues boarded the plane by charging up the front, left emergency chute that most of the passengers had already used to exit the burning craft.

"If he can do it, I can do it," Fire Department Lt. Chrissy Emmons said she told herself before clambering up the chute after Monteverdi.

As the firefighters made their way to the back of the plane, they saw San Francisco police officer Jim Cunningham racing up the aisle toward the cockpit without safety gear.

Cunningham said he was just finishing a patrol of an unoccupied airport building when he heard a fellow officer calmly report over the radio that a Boeing 777 had crashed. Cunningham said he screamed at the driver of an ambulance that happened to be nearby to follow him onto the runway where he could see the smoking wreckage.

When he arrived, he and another officer tossed their sheathed knives up to crew members yelling from the door that they needed to cut passengers from their seatbelts. Just then, the officers noticed jet fuel spewing from one of the wings "like it was coming out of a fire hose."

That's when Cunningham and police Lt. Gaetano Caltagirone made the decision to enter the burning plane through the back of the aircraft, which had a large opening since the tail had broken off.

The two helped clear debris out of the way and helped carry passengers off the burning plane. Cunningham even recovered two iPhones, figuring that "worried loved ones" would be trying to contact their owners.

Once everyone was off the plane, Cunningham required about 15 minutes of oxygen treatment. It was then that his wife, home with their 18-month-old daughter, called.

"I told the paramedic to answer and tell her I was all right," he said. But Cunningham said he could hear her voice rising when told that he was undergoing oxygen treatment, so he took the phone to tell her he was fine.