From the Spaceflightnow.com Facebook page discussion about it.
https://www.facebook.com/spaceflightnow?fref=nf
“First stage continued firing until range safety destroyed it. Video shows Dragon capsule came off intact very early after the event. Possiby deployed a parachute as it passed the back of stage 1 but parachute line disappears a few frames later. Very robust structures for stage 1 to keep working and Dragon to survive intact. One other possibility for failure is the Dragon service module. Frame by frame shows the event occurs at the front of the 2nd stage and base of the service module. It is a white cloud not colored (I.e. not hypergolic fuel) so it may have been a pressurant tank)”
Another comment:
“The only reason I have put a premature second stage engine ignition on the list is that the entire ascent is computer/ software controlled. There could have been a wrong number entered for certain events. It’s what downed a Delta 3 and an Ariane 5 launch...miss entered numbers. Now a misinformed computer could have caused all of the other possible events such as pyro-fasteners, over pressurized second stage tanks etc. We will know more once the press conference happens...and then it might be a week or two.”
“First stage continued firing until range safety destroyed it.
...
I wonder if it could have landed if it weren’t destroyed.
If a parachute line appeared, it would have been the drogue chute.
It appears the second stage fuel tanks ruptured with no ignition, for whatever reason.