Thrill of the Kill (2006)

Haunted by her sister's suspicious death, Kelly Holden enlists the help of murder-mystery novelist Graydon Jennings to help solve the crime. Together they discover that Kelly's sibling was living quite the double life -- sleeping with a congressman and fending off a scorned ex-lover! As this salacious story unfolds, Kelly discovers that truth isn't just stranger than fiction -- it can be more evil too!