“...it was unclear why the transmissions stopped. One possibility one person cited was that the system sending them had been disabled by someone on board. “
Many thanks for filling in that info!
Two actions twenty minutes apart?
Deliberate!
Figure the flight radius, given the amount of fuel.
See what refueling/landing points are within that radius.
And what countries within that radius might be “buddies” with the pilots’ countries....
( it sounds like an “inside job”)