It looks to me like the crack started at the journal radius adjacent to the oil hole drilled for the rod journals, proceeded to expand to the oil passage, then let the whole thing split. Hard to say if the crack was already there, or if it appeared after the machining. Some detailed shots of the rod journal radius might help some of the engine guys determine if it was correctly machined. Either way, that oil passage is closer to the journal surface than I imagined. I can see where taking too much off the crank journal, or offset grinding, could weaken that area quickly.
Judging by the shiny spots on the backsides of the bearings, and the bearings themselves, I'd say it looks like the crank was starting to go out of balance for some time before it let go. Those bearings were certainly getting pounded, and they seem to coincide with the journals ahead of the cracked area, which has the least amount of stabilization and also has belt tension pulling on the snout.
Nothing looks damaged bad, and a good check might show the block, heads and possibly even the rods to still be good. I'd be more worried about the rods than the block, but I'd still get it checked and pressure tested, paying special attention to the mains webbing and bolt holes for cracks. The cam journal surface and roller wheels look marred from bearing debris, but not bad. I don't know about rollers, maybe it can be re-polished? The lifters would need rebuilt at the least, I'd think.
