Unofficial, or digital, formats are often sought by readers who may not have immediate access to a physical bookstore or library.
Eleven years ago, Brooke's high school sweetheart, Shane Nelson, was convicted of a brutal crime—the murder of three people, including Brooke's best friend.
Readers want immediate access to the story after seeing it trending on social media.
The Inmate succeeds because it combines the "small town secrets" trope with the claustrophobic tension of a prison thriller.