I never did answer 
Eomer why I so strongly suspected 
The Elf Warrior.
I think it boiled down to two good reasons and one bad one (sorry to have to admit):
1. He "protested too much", and since he was a rookie, that stood out to me.  "I'm not a werewolf."  "I'm innocent".  Very many posts included that.  It set my suspicion antennae going.
2. He defended 
Wilwarin at a time when both he and 
Wilwa were on my suspect list.  Now, I could have surmised from it that these two might be shirriffs, which actually might have made more sense, but onto my third bad reason.
3. I didn't know 
Elf Warrior that well, whereas I'd gotten rather familiar with 
Eomer, Feanor, Guy, Oddwen, Morm, Wilwarin, and many others who have either played the game before or I'd had contact elsewhere on these boards.  That was not the case with 
Elf Warrior, and I fell to a natural (and illogical) suspicion of unknowns.  My bad.  Lesson learned. 
 
4. Oh. And he didn't play along with my astrology roleplay, so I was ticky-poohed with him on that score too.  Make that TWO bad reasons.  
 
 