Walter and Carolyn Allanson had disliked their son's new wife from the start, and less than two months after the wedding they were dead. On July 3, 1974, police called to their home in Atlanta found Carolyn sitting upright on the basement steps, shot dead, and through the basement window saw Walter lying on the ground, shot several times. Their son Tom had been seen at the house, and a man matching his description had been seen running away. He was arrested, and his wife, Pat, told investigators a string of stories meant to give him an alibi; his own story was also false, and the two did not match. Tom Allanson was convicted of murdering his parents and sentenced to life. Pat was never charged over their deaths, though the suspicion that she had pushed him to it followed her afterward.
She had been born Mary Lynn Patricia Vann on August 22, 1937, in Wilmington, North Carolina, and at fifteen married Gilbert Taylor, an Army sergeant, in Atlanta; they had three children, Susan, Debbie and Ronnie. In 1972 she left them. On May 9, 1974, she married Tom Allanson, six years younger, in a ceremony in which they dressed as Scarlett O'Hara and Rhett Butler, and the couple bought a fifty-two-acre farm near Zebulon, Georgia, where they planned to raise and show Morgan horses.
With Tom in prison she turned to his grandparents, the elderly couple the family called Paw and Nona Allanson. She made herself their companion and caregiver and was named the main beneficiary of their will. Then they fell ill, and tests found arsenic. Around the same time her house and barns burned down, and she was accused of forging Tom's signature to collect the insurance. She was arrested in August 1976 for the attempted murders of the grandparents, tried in 1977 and convicted, and she served about eight years. Both grandparents survived.
Released, she found work as a nurse with a wealthy Atlanta couple, James Crist Sr. and his wife. Both became ill, and James Crist died. Facing prosecution again, she reached a plea agreement, criticized at the time, under which she admitted seven charges, among them theft, attempted murder and posing as a registered nurse, in exchange for an assurance that she would not be charged with Crist's murder or investigated further over the deaths of Tom's parents. She was sentenced to eight years, and she was released in 1999. The year of that prosecution is usually given as 1991.
No court ever found that she killed anyone. Most of what is known about her comes from Ann Rule's book Everything She Ever Wanted, published in 1992 and built on court records and interviews, which gave the story its shape and was adapted for television. Tom Allanson served his sentence, and after his release, according to later accounts, he and Pat were reunited.