Hoo boy...
So its a fresh embark on a really cool site (large river emptying into ocean and a huge cavern with pit below my mostly-above-ground fort), my dwarves go about their dwarfy stuff for about a year without incident, until one day a dwarf named "LedM1", sick of drinking the same booze and eating the same food while working in the rain for months on end starts tantruming, throwing food and drink into the ocean and starting fights. One thing leads to another, dwarves start going crazy, workshops get destroyed, a few murders, a few suicides... y'know, a tantrum spiral. C'est la vie!
I decided to abandon and reclaim with a fresh set of uncrazy dwarves. Almost a year goes by with dwarves doing their dwarfy stuff once more, putting the bodies of their predecessors away/making slabs, building buildings and moving food into stockpiles... when suddenly a dwarf was attacked and killed by the violent ghost of "LedM1"! That jerk!
Having thought I had had him buried, I checked the coffins and sure enough there was a coffin designated for him... but no body inside. I then tried to have a slab engraved for that jerk, but his name was not among those I could memorialize for some odd reason. I looked around for his body, but could not locate it anywhere (even checked the river, ocean, and cavern, no luck). Then he murdered another dwarf.
It seems that until I find his body... no idea where it is or even if its recoverable, I will have a murderous ghost plaguing my fort. And yes, the reclaim party is close to tantruming after the murders of their friends. Curse you "LedM1"! Curse youuuuu!