Evil at Heart by Chelsea Cain
Wow!!! I could NOT put this book down - thank you to Lori LORI'S READING CORNER for sharing her ARC with me!!
This is the 3rd book in the series with Archie and Gretchen, and it's a great addition. It picks up 2 months after the 2nd book ends, with Gretchen on the loose and Archie in a mental hospital.
When some bodies are discovered, the police suspect that Gretchen is back to her old ways and Archie is pulled into the investigation, and back into Gretchen's reach.
Definitely a must-read!