Executions are on hold in the US state of Oklahoma amid concerns about a drug used in lethal injections.
Richard Glossip, who had been scheduled to die tonight, and two other prisoners, have been given temporary reprieves by the United States Supreme Court while it reviews the use of the drug.
Associated Press reports that Dale Baich - a lawyer representing death row prisoners - said "Midazolam is an inappropriate drug to use in executions. The scientific evidence tells us that even the proper administration of midazolam can result in an inhumane execution."
Last year, there was an outcry when a prisoner was left writhing in pain for 43 minutes before he died of a heart attack.
Clayton Lockett, a convicted killer and rapist, was put to death by lethal injection. The process took well over the expected time of a little more than 10 minutes.
The incident drew widespread condemnation, including from US President Barack Obama.
Since then executions have been delayed as states reviewed their execution procedures.
Anti death penalty campaigner Sister Helen Prejean says Oklahoma is under the international spotlight:
