John David Duty was born on April 25, 1952, in Oklahoma. He came from a troubled background, growing up in a broken home with his mother remarrying multiple times. He had several siblings and half-siblings, and later in life used the surname Hall due to confusion about his biological father. As a child, he lost one eye in an accident and suffered a serious head injury after a wall collapsed on him.

Before his criminal path, Duty held jobs at fast-food chains and PepsiCo, and even worked as a manager at a manufacturing company. He was married and had three children. However, in 1978, everything changed when he committed a violent crime that would shape the rest of his life behind bars.

In February 1978, Duty and an accomplice robbed a convenience store in Altus, Oklahoma, and abducted a female clerk, whom Duty later raped and shot three times in the head. Miraculously, the woman survived. Duty fled across the state line to Texas but turned himself in weeks later. In July of that year, he pleaded guilty to rape, robbery, shooting with intent to kill, and kidnapping. He was sentenced to multiple life terms.

Even in prison, Duty was volatile. In 1979, he held eight people hostage in the prison medical unit. While he released all hostages safely, the incident marked him as high-risk and dangerous.

By 2001, Duty had already served over two decades in Oklahoma State Penitentiary when he committed his most notorious crime. On December 19, 2001, he strangled his cellmate, 22-year-old Curtis Wise, using a shoelace. Duty later admitted that he offered cigarettes to Wise in exchange for allowing himself to be tied up to fake a hostage scenario. Instead, Duty murdered him. He even wrote a chilling letter to Wise’s mother admitting to the killing without remorse.

Duty claimed he committed the murder solely to secure a death sentence, stating he would kill again if left alive. He pleaded guilty and refused to allow any mitigating evidence in his defense. During trial, the victim’s mother begged the court for a life sentence, but the judge ruled that Duty was a textbook example of someone deserving execution.

Duty’s case became historic when a shortage of the usual execution drug, sodium thiopental, forced Oklahoma to use pentobarbital for the first time in U.S. history. His legal team challenged the method, claiming it might cause undue pain, but the courts upheld its use. On December 16, 2010, John David Duty was executed at the same prison where he had killed Curtis Wise. He became the first person in the U.S. to be executed using pentobarbital.