Deadly Little Secrets: The Minister, His Mistress, and a Heartless Texas Murder is a 2012 true crime book written by the non-fiction author and novelist Kathryn Casey and released by HarperCollins about the 2006 murder by Baptist minister Matt Baker of his 31-year-old wife, Kari Baker, and the staging of her death as a suicide.

On April 7, 2006, Kari Baker, an elementary school teacher, was found dead in her bed, in the family's bedroom in Hewitt, near Waco, Texas, in what her husband Matt told authorities was a suicide.

The book explores Baker’s double life, examines the physical evidence against him, and includes 80 interviews with police, attorneys from both sides, family, friends, church, and community members.

[3] Upon the book's release, Casey appeared on KABB-TV Fox San Antonio’s “Daytime at Nine” show, telling the host, “Matt Baker almost got away with killing his wife.” Baker had left a typed, unsigned suicide note, and police originally believed it had been written by the wife, who was thought to have died from an overdose of sleeping pills.

[5][6] The book, Casey told the San Antonio Express-News, shows the need for "good, thorough police work at the scene of a suspected suicide."