The Night Shift from Alex Finlay

On New Year's Eve 1999, someone murdered 3 teenage girls and their boss at a Blockbuster Video store. One girl (Ella) survived. Fifteen years later, someone murdered 3 teenage girls working at an ice cream shop. Once again, one girl (Jesse) survived. A teenage boy named Vince was the suspect in the first murders. But he has disappeared. Which makes people wonder if he might not also be the one behind the second murders. On the case, along with the local cops are a very pregnant FBI agent named Keller and a young cop named Atticus. Jesse befriends Ella, who suspects Jesse knows more about the ice cream shop murders than she's saying. And Keller's not so sure Vince was really guilty of the video store murders. There are lots of intriguing plot twists along the way before a bang-up finale.