According to the Kirkus review, Veronica was a bully in a previous book who in this sequel gets a backstory, which the reviewer connects (rightly, in my opinion) to the previous book pair A Dog on Barkham Street and The Bully of Barkham Street (Mary Stolz). All I remembered about it was the line about "Veronica Ganz/Doesn't wear pants." https://www.kirkusreviews.com/book-reviews/marilyn-sachs/veronica-ganz/