Page 738!

I don’t know exactly why or when I got it into my head that the Bullfinch cops would have attired based loosely on old-tyme English bobbies, but there y’go.  For some reason it just made sense.

If it’s not clear (and it may not be), the Bullfinch constables use whistles, hence the ‘tweet’ sounds.  I think it’s mostly clear, but you never can tell.