Wanda Jean Allen was born in 1959, the second of eight children. Her mother was an alcoholic; her father left home after Wanda’s last sibling was born and the family lived in public housing and scraped by on public assistance.  At the age of 12, Allen was hit by a truck and knocked unconscious, and at 14 or 15 she was stabbed in the left temple. It was found that Allen’s actual abilities were markedly impaired, and that her IQ was 69. Found particularly significant was that the left hemisphere of her brain was dysfunctional, impairing her comprehension, her ability to logically express herself, and her ability to analyze cause and effect relationships. It was also concluded that Allen was more chronically vulnerable than others to becoming disorganized by everyday stresses, and thus more vulnerable to a loss of control under stress.  By age 17, she had dropped out of high school.

In 1981, Allen was sharing an apartment with Dedra Pettus, a childhood friend-turned-girlfriend. On June 29, 1981, they got into an argument, and Allen shot and killed Dedra. In her 1981 confession, Allen stated that she accidentally shot Pettus from roughly 30 feet away while returning fire from Pettus’s boyfriend. However, the forensic evidence was inconsistent with Allen’s story; in particular, a police expert believed that bruises and powder burns on Pettus’s body indicated that Allen had pistol-whipped her, then shot her at point-blank range. Nevertheless, prosecutors cut a deal with Allen, and she received a four-year sentence in exchange for a guilty plea to a manslaughter charge. She served two years of the sentence.  Pettus was buried at Trice Hill Cemetery in Oklahoma City, Oklahoma.

Seven years after the death of Dedra Pettus, Allen was living with her girlfriend Gloria Jean Leathers. The two met in prison and had a turbulent and violent relationship. On December 2, 1988, Leathers, 29, was shot in front of The Village Police Department in Oklahoma City. Fifteen minutes before the shooting, the two women were involved in a dispute at a grocery store. A city officer escorted the two women to their house and stood by while Leathers collected her belongings. Leathers and her mother were on their way to file a complaint against Allen. When Leathers exited the car, Allen fired one shot, wounding Leathers in the abdomen. Leathers’ mother witnessed the shooting. Two police officers and a dispatcher heard the shot fired, but no police department employee witnessed the shooting. The police recovered a .38-caliber handgun they believe was used in the shooting near the women’s home. Gloria died from the injury three days later, on December 5, 1988.  Leathers was buried at Green Acres Memorial Gardens Cemetery, Sperry in Tulsa County, Oklahoma.

The state charged Allen with first-degree murder and announced that it would seek the death penalty. Evidence that Leathers had a history of violent conduct, and that she had stabbed a woman to death in Tulsa, Oklahoma in 1979, was central to the self-defense argument at Allen’s trial. Allen testified that she feared Leathers because she had boasted to her about the killing. The defense sought to corroborate this claim with testimony from Leathers’ mother, whom Leathers had told about the stabbing. However, the prosecution objected, and the court prohibited the introduction of such testimony because it was considered hearsay. The prosecutor depicted Allen as a remorseless liar. The jury found her guilty of first-degree murder and sentenced her to death.

During the punishment phase the prosecutors argued that Allen should be sentenced to death because she had been previously convicted of a felony involving the use or threat of violence; that she was a continuing threat to society; and she committed the murder to avoid arrest or prosecution. The jury found that the first two aggravating circumstances existed in Allen’s case. Her defense presented numerous mitigating circumstances including good relationship with her family, good work habits, and her fear of the victim.  In the sentencing phase the prosecution presented testimony on the circumstances of the death of Detra Pettus, and compared this previous crime to the death of Leathers.

In a 1991 affidavit, the defense lawyer stated that after the trial he learned that when Allen was 15 years old, her IQ was measured at 69, placing her “just within the upper limit of the classification of mental retardation” according to the psychologist who analyzed her and that an examining doctor had recommended a neurological assessment because she manifested symptoms of brain damage. The lawyer stated, “I did not search for any medical or psychological records or seek expert assistance for use at the trial.”  A psychologist conducted a comprehensive evaluation of Allen in 1995 and found clear and convincing evidence of cognitive and sensory-motor deficits and brain dysfunction possibly linked to an adolescent head injury.

Allen spent 12 years on death row. Her application for clemency was denied.  Allen, then 41, was executed by lethal injection by the State of Oklahoma on Thursday, January 11, 2001 at Oklahoma State Penitentiary in McAlester. Twenty-four relatives of murder victim Gloria Leathers and manslaughter victim Detra Pettus traveled there for the execution. Many of them watched the execution from behind a tinted window. While lying on the execution gurney, Allen said, “Father, forgive them. They know not what they do.” She also stuck her tongue out and smiled at her appeal lawyer, Steve Presson, who had become her friend. He says she was “dancing on the mattress, while they tried to kill her.” She was pronounced dead at 9:21 p.m. Relatives of Leathers expressed the execution gave them “closure.”  She was buried at Trice Hill Cemetery in Oklahoma City.