Coroners investigating the crash of a Cypriot airliner that killed 121 people expect the results of tests that could indicate whether fumes knocked passengers and crew unconscious.
A team of six coroners was conducting a series of toxicology tests on some of the 118 bodies recovered from the crash site on a mountainside north of Athens. Crews were still searching for three bodies, The AP reported.
The coroners said they expected test results to indicate whether those on board the Boeing 737-300 had inhaled carbon monoxide, which could have knocked them out.
Tests for other substances will take longer, they said.
But if the results of all toxicology tests are negative, coroners would not be able to rule out that some other factor could have made people on board lose consciousness, coroner Nikos Kalogrias said.
Autopsy results on 26 bodies identified so far have shown that some passengers and at least four crew members _ including the co-pilot _ were alive, but not necessarily conscious, when the plane went down last weekend. The body of the plane's German pilot has not been identified, and it is unclear whether he is one of the three still missing.
Helios Airways Flight ZU522 from Larnaca, Cyprus, to Athens crashed Sunday.
Chief investigator Akrivos Tsolakis told the AP on Thursday that an air traffic control diagram showed the plane had flown - on automatic pilot - to the Greek capital's international airport. But it was flying at 34,000 feet (10,360 meters) and turned south into a holding pattern over the island of Kea after passing over the airport. More than an hour later, it changed course again and later crashed north of Athens.
"What troubles us is that the automatic pilot was functioning up to a certain point, and then it was disengaged, possibly by human action," Tsolakis said.
Tsolakis said the automatic pilot had been programmed to fly the plane to Athens airport, and it was unclear how or why it was disengaged.
"Possibly, there was human intervention. I'm not speaking with certainty, because I don't have all the evidence yet," Tsolakis stressed.
The strange circumstances of the flight - and disturbing scenes witnessed by F-16 fighter pilots scrambled to intercept the plane - have baffled authorities. Officials have said there are no indications of sabotage or terrorism.
According to the government, the two F-16 fighter pilots, who first established visual contact with the plane while it was flying above Kea, reported seeing the co-pilot slumped over the controls, apparently unconscious.
They said the pilot was not in his seat, and they also later saw what appeared to be two people trying to regain control of the plane. Oxygen masks were seen dangling from the ceiling of the passenger cabin, the government said, citing the F-16 pilots.
Tsolakis said investigators were still examining the possibility that those on board were knocked unconscious by sudden cabin decompression.
Some answers could be provided by the contents of the plane's flight data recorder, or black box, which was sent to Paris for decoding. Tsolakis said he expected to receive some results from France soon.
France's Inquiry and Analysis Bureau, which was analyzing the recorder, said the box "was exposed to fire but its external appearance shows no deformations linked to the impact."
However, the agency stressed that it would not disclose any information from the analysis since Greece was handling the investigation.
Tsolakis has he has never encountered such a case. "In my career, going back 50 years as an airman and as a safety officer, I have never seen anything that resembles this," he said.
But he said investigators had received almost all the information they needed from Greece, Cyprus, Britain and other European countries about the airline company, the plane's maintenance record, the history of the pilot and co-pilot and accident statistics, and could have preliminary results in about 10 days.
Authorities have still not released the full account of what the fighter pilots saw, or anything about the passenger jet's final 23 minutes of flight.