All along, I’ve thought: This plane will turn up any minute. Now, though, I’m wondering. The search for Malaysia Airlines Flight 370 has not yet expanded to Venus and Mars but it’s still extremely broad, basically from Russia to the southern Indian Ocean.

There’s increasing suspicion that this was a deliberate act, a crime, but I would not rule out an accident, such as a Payne Stewart situation (decompression, plane keeps flying). Most of all, as I said the other day, I’d be wary of any single data point, or news nugget. Stay skeptical. Today’s breakthrough revelation could be retracted tomorrow.

For example, one of the big stories of the weekend has evaporated: Everyone reported, based on Sunday’s official briefing from Malaysian authorities, that the ACARS system was turned off (or became disabled somehow) before the pilot (actually the co-pilot) said “All right, good night.” That seemed significant because it suggested deception in the cockpit. But at the presser today in Kuala Lumpur, the Malaysian briefer walked that back and said they don’t know when the ACARS system shut down. It could have happened after the “good night” communication.

From an unofficial transcript (thanks to my colleague William Wan):

Q: What time was the ACARS disabled compared to co-pilots last words?

CEO: The last ACARS transmission was 1:07. Okay, we don’t know when the ACARS was switched off after that. It was supposed to transmit 30 minutes from that, another transmission, but that transmission did not come through. That was the very last transmission data. When it was switched off? Any time between then to next 30 minutes.

As far as…pilot communication I understand according to record it was at 1:19.

This investigation has been anything but smooth and reassuring. It took many days for the Malaysian military to reveal that its radar had picked up the plane heading west. We’ve seen Chinese satellite images of possible wreckage turn out to be nothing significant. This is obviously torture for the families of the passengers and crew (see William’s heart-stopping story).

For the rest of us it’s a compelling mystery. Could the pilot or co-pilot have climbed to 45,000 feet and lowered the pressurization in the cabin to asphyxiate the passengers? Conceivably, but why? Where’s the motive? Not much make sense in this tragedy. As the U.S. official said in our story Sunday, when asked if this could be a hijacking, “Where are the demands?”