Where He Can't Find You - Darcy Coates

DON'T WALK ALONE, OR THE STITCHER WILL FIND YOU.
Abby Ward lives in a town haunted by disappearances. People vanish, and when they're found, their bodies have been dismembered and sewn back together in unnatural ways. But is it the work of a human killer...or something far darker?
DON'T STAY OUT LATE, OR THE STITCHER WILL TAKE YOU.
She and her younger sister live by a strict set of rules designed to keep them safe―which is why it's such a shock when Hope is taken. Desperate to get her back, Abby tells the police everything she knows, but they claim their hands are tied.
DON'T CLOSE YOUR EYES, OR THE STITCHER WILL REMAKE YOU.
With every hour precious, Abby and her friends are caught in a desperate game of cat and mouse. They have to get Hope back. Quickly. Before too much of her is cut away. And before everything they care about is swallowed up by the darkness waiting in the tunnels beneath the home they thought they knew.