Execution by lethal injection is seen by many Americans as a less barbaric alternative than older methods like hanging, firing squads and electrocution. It is easy to assume that the process must resemble euthanasia procedures for terminally ill people or pets. The reality is very different, says Corinna Barrett Lain, a law professor and death penalty expert.

Lain didn’t initially intend to make the death penalty her primary area of study, she tells the ABA Journal’s Lee Rawles in this episode of the Modern Law Library. A former prosecutor in Virginia, Lain did not begin her work out of opposition to the death penalty. But the more she discovered about the realities of the administration of lethal injections, the more she was compelled to demystify the process.

In Secrets of the Killing State: The Untold Story of Lethal Injection, Lain upends a lot of conventional wisdom about lethal injections. For example, the three-drug protocol used by most states was not a drug cocktail arrived at through scientific research. Rather, in 1977, after the U.S. Supreme Court allowed executions to resume after a 10-year hiatus, Oklahoma medical examiner Dr. Jay Chapman was asked by a state legislator to come up with an alternative to the state’s rickety electric chair. Though Chapman admitted he was “an expert in dead bodies but not an expert in getting them that way,” he proposed combining sodium thiopental, pancuronium bromide and potassium chloride. “You wanted to make sure the prisoner was dead at the end, so why not add a third drug,” the book quotes Chapman as saying. “Why does it matter why I chose it?” In contrast, an overdose of a single drug, pentobarbital, is what is commonly used by veterinarians in animal euthanasia.

“Lethal injection is not based on science,” Lain writes. “It is based on the illusion of science, the assumption of science.”

In this episode, Lain and Rawles also discuss botched executions, shady sources used by states to procure the drugs used for lethal injections, and how Lain’s scholarship has impacted her views of capital punishment as a whole.