An Oklahoma death row prisoner died of a heart attack roughly 20 minutes after waking up during his execution mid-injection, due to faulty equipment. The scheduled execution of a second inmate for the evening was subsequently postponed.

Corrections Director Robert Patton stopped the delivery of the three drug combination used in Oklahoma, after realizing inmate Clayton Lockett had regained consciousness after being sedated at the start of his execution. Patton attributed the botched procedure to a vein failure which prevented all three chemicals from efficiently entering Lockett’s system.

An eyewitness described the scene – Lockett grimaced and tensed his body several times over a three minute period before the execution was shielded from the press. After being declared unconscious ten minutes into the process, Lockett spoke at three separate moments. The first two were inaudible, however the third time he spoke, Lockett said the word “man.”

Those against the death penalty took to Twitter:

The botched execution in Oklahoma is the quintessential example of how and why the death penalty is cruel and unusual punishment.

— MsLadyLawyer (@MsLadyLawyer) April 30, 2014

One day, I'm going to wake up and discover Oklahoma has actually made it to the 21st Century.

— Jennifer McClintock (@jeninthe405) April 30, 2014

What happened in Oklahoma today is deeply, deeply disturbing.

— Michael Li (@mcpli) April 30, 2014

How could Oklahoma botch an execution? If there’s one thing I would expect Americans to know how to do by now, it’s kill somebody.

— God (@TheTweetOfGod) April 30, 2014

Lockett, 38, convicted of shooting 19-year-old Stephanie Neiman and having her buried alive in 1999, died of cardiac arrest 43 minutes after the first drug was administered. The press was shielded from the event after Lockett woke up and began speaking, 16 minutes after the execution began. Lockett died roughly 20 minutes later. “It was extremely difficult to watch,” Lockett’s attorney, David Autry, said afterward.

A second death row inmate, Charles Warner, was scheduled to be executed at 8 p.m. Tuesday evening, which will be rescheduled due to the equipment error. Warner, 46, was convicted of raping and killing an 11-month-old in 1997.

The state of Oklahoma botched an execution Tuesday night, creating a macabre scene, according to witnesses. http://t.co/cvemaL6juk

— Mashable (@mashable) April 30, 2014

There has been some controversy in Oklahoma regarding a policy to not reveal the source of the drugs used for lethal injections.

Both Lockett and Warner had sued the state for failing to disclose details regarding the source of the execution drugs, which resulted in the Supreme Court issuing a stay of execution for Lockett. This stay was eventually revoked, then replaced by another extension issued by Governor Mary Fallin, which is the reason why Lockett and Warner ended up being scheduled to die on the same day.

I've postponed tonight's second execution and ordered an evaluation of Oklahoma's lethal dosage protocol.http://t.co/hqMhY3tX6J

— Governor Mary Fallin (@GovMaryFallin) April 30, 2014

Oklahoma tonight tried an untested new formula for lethal injections shrouded in secrecy countenanced by governor, legislature, and courts.

— Andrew Cohen (@CBSAndrew) April 30, 2014

Image via Wikimedia Commons