To answer the previous post: He spawns at the front entrance of NWT (On Xev, that means North West Top, the set of buildings in the Northwest section of the zone). He then continues walking east into NHS (North Hero Shrine: the north corridor first, then the south corridor), walks back west out of NHS and into the intersection, and then walks south. I haven't followed him after that, but he will eventually return and go back to the entrance of NWT to repeat his patrol.
Anyway, the original intent of this post is to question the validity of this mob dropping the Girdle of Mithaniel. I have soloed NHS for at least 50 AAs and in that time, I would have to say that I have killed Lieutenant Roset Beatry at least 50 times. In all that time, I have never witnessed him dropping the girdle. Someone has posted that he looted one off of him awhile ago. I am just wondering if I am having bad luck with this drop; has anyone recently looted this girdle off of him? Allakhazam's says that this drop is Uncommon; I am led to believe that it is either Rare or Incorrect Drop Information.