A midair heat flash from Metrojet Flight 9268 was detected by a US military satellite before the plane crashed Saturday in Egypt's Sinai Peninsula, a US official told CNN.
Intelligence analysis has ruled out that the Russian commercial airplane was struck by a missile, but the new information suggests that there was a catastrophic in-flight event — including possibly a bomb, though experts are considering other explanations, according to US officials.
There are a wide range of theories on what made the passenger jet plunge to the ground, killing all 224 people on board, but Russian officials say it's too soon to speculate on the cause.
Aviation experts agree, and officials have downplayed an apparent claim by Islamic militants that they brought down the Airbus A321-200, saying technical failure is the most likely reason for the crash.
