In "Presumed Guilty, Casey Anthony: The Inside Story," Jose Baez said detectives should have realized Anthony had built a "fantasy world," and her lies weren't evidence of guilt but signs of someone with "serious mental health issues."
The 421-page book is scheduled for release July 3.
Describing how Anthony led detectives on a wild goose chase, even taking them to Universal Studios where she falsely claimed she had a job, Baez writes, detectives "should have stopped and realized, `Wait a minute, we're not dealing with someone who is playing with a full deck.'"
Anthony originally told detectives that her daughter, Caylee, was taken by a babysitter in June 2008, and that she didn't report her missing for more than a month because she was searching for the toddler on her own. During Anthony's trial last year, Baez argued that the little girl accidentally drowned in the family swimming pool while Anthony and her father, George, were at home. Anthony panicked from the traumatic effects of being sexually abused by her father and George Anthony hid the body, according to the defense argument.
George Anthony denied the defense's allegations that he abused Casey and helped her cover up Caylee's death.
Prosecutors had contended that Anthony suffocated Caylee with duct tape because she wanted to be free to hit the nightclubs and spend time with her boyfriend. Jurors acquitted Anthony of first-degree murder but convicted her of four misdemeanor counts of lying to investigators.
Anthony is currently serving probation for an unrelated charged at an undisclosed location in Florida.