Time to quote the second e-mail from "???" who hopefully gets revealed later in the game.
"The mysterious figure is known as Kite of the Azure Flame, the title was recieved after the Epitaph of Rebirth. (Might have mistranslated that one, however it is porbably the name of the event.) The character itself no longer exists however the data of the character still wanders as an incomplete being, however something on the data is causing it to act the way it does now."
I wouldn't be suprise if that was Helba actually, guess we'll find out in voulme 2 or 3, anyways, I'm guessing that it's the Bracelet itself that does it, not a virus. It'd be to simplistic if it was a virus.
As for the end, it was because of another anomynous e-mail, though it was typed up in leet talk, but I was able to translate it close to something like "At (Keywords here) there is a vaccine that is able to destroy the AIDA please, hurry before it's too late." (Have no clue who this person is either Aura? Doubt it, but dunno). But the Locker itself actually contained AIDA.