It boils down to different types of evidence. U.S. and British officials point at intelligence and security concerns at the Sharm el-Sheikh airport as they say it's likely a bomb caused the October 31 crash in Egypt's Sinai Peninsula. Egyptian authorities say forensic evidence from the scene will reveal what happened to the doomed jet.
If history is any indication, it could be a long time before these governments can get on the same page. But here's a look at what we know so far from the evidence that's been made public:
• Flight 9268 dropped off radar about 23 minutes into its journey, and tracking data showed
abrupt changes in speed and altitude before the signal was lost.
• Air traffic controllers received no distress calls, suggesting the disaster happened suddenly.
• A U.S. military satellite detected a midair heat flash before the plane crashed. That could happen if a bomb went off, but other things could have caused it, analysts say.
• The Sinai Peninsula, where the plane crashed, is a volatile region that has been a battleground between ISIS-affiliated militants and Egyptian security forces. Hundreds have died in the fighting, and the militants have bomb-making capabilities.
• ISIS has repeatedly claimed it downed the jet. One purported message from the group's Sinai affiliate said ISIS brought down the jet to retaliate against Russia
for airstrikes in Syria
• Russia started launching airstrikes in September, saying it was coordinating with the regime to combat ISIS and other terrorists.
• Chatter surrounding the crash
in internal messages of the terrorist group drew the attention of the U.S. intelligence community, a U.S. official said. This chatter was picked up only after the plane went down and included talk of a bomb's origins and braggadocio about the crash, U.S. officials said.
• Alexander Smirnov, a Metrojet official, told reporters in Moscow the airline had ruled out technical problems and human error. Protection systems on the plane would have prevented it from crashing, he said, even if there were major errors in the pilot's control equipment.
• Intelligence suggests someone at the airport helped plant a bomb on the plane, U.S. officials have said.
• Egyptian officials have maintained that the Sharm el-Sheikh airport measures up to international standards, but concerns have been raised about security there in the past
. British officials temporarily suspended flights from the airport to the United Kingdom last week amid security concerns. Days later some flights from Sharm el-Sheikh to Britain resumed with new security measures in place. On Friday, Russian President Vladimir Putin also agreed to suspend Russian air traffic with Egypt until the cause of the crash can be determined --
and a top Russian official said Tuesday that the flights likely won't be resuming any time soon. "It is impossible to drastically change the safety systems, security and control in a week or even a month," Sergei Ivanov, Putin's chief of staff, said Tuesday, according to the state-run TASS news agency.
• European investigators who analyzed the two flight recorders from the plane say the crash was no accident, CNN affiliate France 2 reported
. The investigators told France 2 the cockpit voice recorder of Metrojet Flight 9268 showed an explosion and the flight data recorder confirmed the explosion was not accidental. There was no sign of mechanical malfunction during the initial part of the flight, France 2 reported.
Evidence that calls into question bomb scenario:
• ISIS' refusal to divulge details about the bombing is making some experts skeptical of the terror organization's claim that it was involved in the crash. Typically, ISIS
is quick to trumpet who carried out any attacks and how for purposes of praise and propaganda. To some, the fact that ISIS hasn't provided details in this case raises doubt about the group's repeated claims of responsibility.
• Smirnov, the Metrojet official, was quick to share his thoughts on purported footage of the crash posted by militants claiming credit for bringing down the plane: "Those images you have seen on the Internet, I think they are fake."
• One U.S. official warned that chatter like what was observed in ISIS-affiliated messages after the crash can sometimes be empty boasting or an attempt to misdirect intelligence services.
• Russian state media reported
last week that so far, investigators hadn't found any traces of explosive devices in the debris.
• Most of the bodies retrieved at the crash site
were intact, a medical source in Sinai told CNN, and showed no major burns. On the bodies of victims recovered so far, investigators hadn't found any sign of explosive impact, Russian state media reported Tuesday
, citing unnamed sources. Russia's state-run Tass news agency reported that Russian and Egyptian experts had not found any blast-related trauma during their preliminary examination of crash victims' bodies, citing a Russian source within the investigation.
• Egyptian Civil Aviation Minister Hossam Kamel has said investigators haven't found evidence to support the theory that a bomb was responsible.
• Asked about the possibility of someone sneaking a bomb in through service entrances at the airport, a Sharm el-Sheikh airport employee familiar with security operations said security is tighter for airport employees than tourists. All trucks are scanned before entering the airport, the source said.
• U.S. officials have expressed caution about making assessments without physical evidence, noting that at first, many believed the crash of TWA Flight 800 was a terror attack, but investigators later determined it was caused by a technical issue
. The United States isn't part of the team combing through physical evidence in the crash investigation, and U.S. officials say so far Russian and Egyptian investigators haven't shared physical evidence that would be needed to provide definitive proof.
• A senior intelligence official cautioned
that much of the evidence so far amounts to "hearsay," with no access to debris, bodies or the cockpit voice recorder, which normally would be a key part of a crash investigation at this point.
Evidence that points to other theories:
• Egyptian investigators say they haven't ruled out any scenarios. The possibility of human error, mechanical failure and structural problems with the plane remain on the table. Ayman al-Muqaddam, the head of Egypt's investigation into the crash, told reporters this week that it could have been caused by a lithium battery or a mechanical issue.
• The heat flash picked up by a U.S. military satellite, analysts said, could also occur if there were an engine explosion or a structural problem with the plane that caused a fire.
• Metrojet Flight 9268's tail was found 5 kilometers (3 miles) away from the other plane wreckage and did not show any signs of burning from a fire, state broadcaster Russia 24 reported. That, CNN aviation analyst Mary Schiavo said, could be a sign of botched repair work conducted on the plane after a 2001 tail strike incident. "To me, it says (the tail) exited the plane before the explosive event and before the fire engulfed the plane," she said.