Krentz, Jayne Ann. Fogg Lake series. #1

Title from web page

When Olivia suddenly vanishes one night, Cat frantically begins the search for her friend. No one takes the disappearance seriously except Slater Arganbright, an agent from a shadowy organization known only as the Foundation, who shows up at her firm with a cryptic warning. A ruthless killer is hunting the only witnesses to a murder that occurred in the Fogg Lake caves fifteen years ago, Catalina and Olivia. And someone intends to make both women vanish

Compact discs

Unabridged

Narrated by Sandra Michelle