The "Upper body is gone" just means they died, because the upper body is what everything builds off of. It means everything is gone, but it only shows stuff closest to the center of the body. It's why when someone loses an arm they don't show a missing hand as well.
Ah, gottcha. The fact that there was already a coffin assigned to him threw me. I guess it was assigned when he died, not when they bring him to it?
The only thing I can think of is the act of some ghost. It's possible that any blood splatters were cleaned, although unlikely
He's my fort's first fatality that I'm aware of. To see if there might be something I missed, I went to the craft workshop to look at the "engrave memorial" menu -- the only beings listed there were the mason himself, and a bunch of ant-people (and one named crundle) from the caves.
It's also within the realm of possibility that he fought back against a vampire and was killed in the first hit. I think in that rare case, you don't get a report because the vampire's report invisibility squelches it.
I know that in 40.xx vampires are a lot harder to have outed by citizens. I had one drain 3 bodies in the main meeting hall before I finally figured out who it was. Dwarves were blissfully unaware of who was doing it.
Hmm... he apparently died in front of a LOT of witnesses, but I can't come up with a better explaination right now.
(Checked the justice screen to see if it was listed as a murder, but the only criminals are four random craftspeople that didn't make the Count the trinkets he wanted.)
Off to see if I can find the telltale signes of vampirism in any of my 171 (apparently) living dwarves.