In a Reuters exclusive, the U.S. Department of Justice wanted to execute prisoners with fentanyl last year, at a time when the highly addictive opioid was fueling the worst overdose crisis this country has ever seen.

Documents revealed in court filings last month showed how the department contemplated using the drug. It was then decided against, as Attorney General William Barr in July decided to use pentobarbital instead.

Pentobarbital is a barbiturate that slows the activity of the brain and nervous system. It's expected to be used when federal executions resume later this year, ending a de facto moratorium on the punishment put in place by former President Obama.

The special consideration for fentanyl executions was at a time when federal agents have been seizing illegal imports of the synthetic opioid.

Pharmaceutical companies have attempted to halt their distribution channels into the federal government that would ultimately be used in executions.

This has led to many states, and the federal government to concoct their own deadly recipes. Some of these experimental drugs have led to “botched” executions in which a prisoner died a horrible death, viewed by some as a breach of the constitutional ban on “cruel and unusual” punishments.

In 2017, authorities in Nebraska used the powerful opioid in a lethal injection. It was the state’s first execution in 21 years, and the country’s first death sentence carried out with fentanyl.

According to the three-page internal memorandum from March 2018 by the director of the department’s Bureau of Prisons, the Justice Department was examining the “use of fentanyl as part of a lethal injection protocol."

"The full contents of the memo are not public. It is not known why the department decided to examine fentanyl, what supply channels were considered or why it ultimately rejected fentanyl as a protocol. The government’s court filing shows the only other named drug examined as the subject of a department memo was pentobarbital, the drug it now says it wants to use in December and January to kill five of the 61 prisoners awaiting execution on federal death row," Reuters said.

Reuters spoke with Mark Inch, who was the Bureau of Prisons’ director at the time, acknowledged that he wrote the memo, had to resign a couple of months after writing the memo, and he wouldn't comment further.

One Ohio lawmaker earlier this year proposed using illegal fentanyl seized from drug traffickers to execute inmates.

Robert Dunham, the director of the Washington-based non-profit group the Death Penalty Information Center, told Reuters "there is just something fundamentally wrong about using a drug [fentanyl] implicated in illegal activities as your method of executing prisoners.”