A U.S. official tells CNN Malaysia Airlines Flight 370 flew erratically and registered dramatic changes in altitude on the morning it vanished a week ago.
For the families of passengers of the missing plane - it's been an agonizing wait for answers.
They are still clinging to some hope that their loved ones have landed somewhere and are still alive.
CNN's David McKenzie is OutFront in Beijing and he spoke to a family member who hopes Flight 370 was a victim of a hijacking.
"This situation has broken my heart," Father of a Flight 370 passenger said. "My tears have run dry. I hope the plane was hijacked, because then at least there is hope."