Do you think there will be a sequel series? (WARNING: SPOILERS AHEAD)

In the second epilogue, Sabrina grabbed a dagger so she could fight off any monster when Allison screamed. I initially thought tha Sabrina was threatened by some gang, but when re-read, it said that she had "seen their symbol in the streets". Do you think "their symbol" is the red handprint? If so, do you think it's a set-up for a new set of books, or just something to tease us?