no! rosa is most defenetly not the criminal here.
its a 'story' about the real criminal of the first twilight and rosa's action. rosa is most defenetly inocent in this riddel.
AuraTwilight you talked to me?if you did, i do belive that the door was locked at the 2nd day when rosa unlocked it (like we saw) but it was open in the first day until very early in the morning of the 2nd day where the culrpit (not rosa) locked it.
BTW cao ni ma, rosa is not really the detective, actully she did an action that if you notice what she did, your mind will imidiatly yell "she is the culrpit!"
-edit-
opsy, i forgot 2 importent things in my 'tale'.
the first one is the notice that shanon found in the dining room.
the culrpit probebly put that notice after he locked the chapel, becuse if some servent will enter the dining room and see the notice there while the chapel is open... its bad end for the culrpit. (i hop you understnd what i mean)
the 2nd one is the gold. 3 bars of gold that were inside the chapel, i could slip it into the decoration category, however its pretty much show rosa's inocent (in my eyes at least)