After seeing the new on scene video of not just the stabilizers but also what appear to be the air frame mid section there are no burn marks. No cratering in the desert. Seems like the debris fell more or less straight down.
Now obviously I am no expert - but I play one on FR,hehehe - my guess is now that the engine shut down the restarted with a force that exceeded the air frame design.
It tore the stabilizers off and then the main air frame failed.
FWIW a professional photographer on scene says he say the engine start and restart. Saw debris fall to earth near him.
He and others ran to the wreckage and found what was left of the cockpit with the body of the co pilot still in his seat.
I’m going with catastrophic air frame failure possibly as a result of and engine malfunction.
Agreed, I’m no expert and I’m not there, but I think “structural failure” is the culprit.
There’s reports of the engine shutting down after 6 seconds then restarting and exploding, so that’s consistent. Keep in mind that the descent profile of the spacecraft was supposed to be belly first straight down at that point so how it descended wasn’t uncharacteristic of the craft.
Probably as you say, engine explosion blew the craft apart.