Academy

The behavior gives it away, it's definitely Arandor.

I'm almost certain there's a connection to Holmes here.

Possibly. The most "Holmes-like" Holmes for me is Livanov, and he was supposedly beardless, but one of the character's traits is cosplay, so if we consider the keyword "fake," everything falls into place.

By the way, just for fun, you could tell the killer that there's evidence against him, so he starts making up alibis for others.

Why bother, when I'm here for the barbarians?