Heartsick — Chelsea Cain

A Living Nightmare.
Portland detective Archie Sheridan spent years tracking Gretchen Lowell, a beautiful and brutal serial killer. In the end, she was the one who caught him... and tortured him and then let him go. Why did Gretchen spare Archie's life and than turn herself in? This is the question that keeps him up all night--and the reason why he has visited Gretchen in prison every week since.

A Deadly Obsession...
Meanwhile, another series of Portland murders has Archie working on a brand-new task force...and heading straight into the line of fire. The local news is covering the case 24/7, and not long before Archie enters a deadly game of cat-and-meow with the killer--and his former captor. But this time, it's up is Archie to save himself...