Andrew Zilber authored the book "Interview with a Grue" which was published sometime between 883~949 GUE. The following is an excerpt from that book:

The air in the room lay deadly still, thick with the stench of a Grue in confinement. I could make out just his faint profile in the darkness, the barest glint of his razor claws, the faintest gurgle of his fetid breath. I took a step closer, and was about to introduce myself, when suddenly the gurgling grew louder--and then a sort of gnashing of great teeth--and then a sort of gnashing of great feet--and lo!--the hulking bully drew a gleaming bone from his jaws, and tossed it to the floor with a grunt. It clattered at my feet, and as I looked down, I saw that it still bore a delicate silver bracelet, wrapped around what once was a slender arm. 

   At that moment, I prayed to the Implementors that of all my assignments as a journalist, this would be only my most repugnant, or perhaps my most difficult -- but, please Yoruk, make it not my last.

SOURCE(S): Zork: Nemesis