>>10232804 (LB)
The flash looked very yellow-ish in the light spectrum. I've never seen ANFO detonate but I would expect it to be more red-ish in color.
The blast had to be some sort of HE munition. The question is was it a cook-off or was it purposely detonated? My money is on purposely detonated. Given everything known so far, this has MOS written all over it.
Means Motive & Opportunity