One of Ann Rule's best. The true story of David Brown, 36, a wealthy computer whiz and psychopath, who persuades his 16-year-old sister-in-law, Patti (whom he’d started grooming for sex from the age of 11) and his 14-year-old daughter, Cinnamon, to rid him of his 22-year-old 5th wife, Linda, mother of baby Krystal. (Supposedly Linda was insisting that he get rid of the two teenagers, who'd lived with them for several years; actually Linda dead was worth a million dollars in insurance proceeds.) As juveniles, he assures them, they would receive only a slap on the wrist. When Patti backs out at the last minute, Cinnamon does the deed, then accidentally survives an ‘attempted’ suicide that was meant to kill her. After she recovers, she is tried and convicted of her step-mother’s murder.
David and Patti quickly forget about Cinnamon; they secretly marry and have another daughter. Five years down the road, incarcerated indefinitely in a prison for Young Offenders, Cinnamon, whose father is paying her little attention, learns about the new baby about the same time as one of the original investigators, never satisfied with the resolution of the case, contacts her … and Cinnamon gives him a more accurate account of the murder.
Eventually this leads to the arrest of David and Patti on charges of conspiracy to commit murder. While in custody, David will attempt to have the investigator, the prosecutor, and Patti murdered by a fellow inmate who's due for release, who will eventually give evidence against him. David is currently serving a life sentence (hopefully, until the despicable creep can rot in hell).