That he was going-around seems fairly evident from the pictures, and to roll through 90 degrees would take more than a "splutter" on the portside - this is an experienced pilot with lots of twin-time; not a GFT.
In my mind I can visualise the aircraft on approach, going-around, *something* happens, rolls left through 90 degrees, yaws left 90 degrees (to nose down) and hits the ground nose down slightly past the vertical then the tail drops and the whole thing slides to a halt.
No fire: But then there was nothing to ignite one and the fuel was on the wing tips in any event.
So I then think about what caused that port wing to drop (or starboard to rise) quite rapidly (all assuming the photo sequence I alluded to previously).
Whether he was asymmetric in the [missed] approach I don't know but will be important and is the only time ACH becomes relevant.
Reasons for a wing drop [in a twin] we all know - wing stalled, asymmetric power/lift, wrong rudder, structural fail of wing, flap deployed asymmetrically. Some of those can possibly be ruled-out by looking at the pictures.