The execution of one of the nation's longest-serving death row inmates was put on hold Wednesday, the latest in a number of botched lethal injections across the country.

Thomas Eugene Creech, 73, was convicted of five murders in three states and was sentenced to death after killing a fellow prisoner in 1981. Lethal injection is the most common execution method in the United States, but officials have struggled to both find the drugs necessary and find suitable veins to inject them into. 

Creech is one of several death row inmates who have had their executions halted in recent years after executioners had trouble placing an IV, a problem that has lingered since the country's first lethal injection was performed in 1982.

 Here's what you should know about Creech’s case and what comes next.

What went wrong in Idaho?

The medical team attempted to establish IV access eight times in multiple places and encountered issues with both accessing the veins and the quality of the veins, department director Josh Tewalt said at a news conference Wednesday. Once the team's leader determined it was unlikely they would be able to establish IV access, they halted the execution, Tewalt said.

In 2022, 35% of the 20 execution attempts were botched because of the incompetence of executioners, failure of protocol or flaws in the protocol design, according to the Death Penalty Information Center. But secrecy laws regarding executions may prevent the public from understanding what exactly went wrong in this case, according to Robin Maher, executive director of the center. Idaho increased secrecy around the drugs used in lethal injections in 2022, according to the center's year end report.

"Based on all of these botched executions, there's no stronger argument for increasing the transparency and accountability of government officials when they're executing people," she said.

Why can't executioners find veins?

During the country's first lethal injection, executioners in Texas struggled to find a suitable vein in Charles Brooks because of his heavy drug use, Fordham University law professor Deborah Denno wrote in a chapter in a forthcoming publication titled “Six U.S. Execution Methods and the Disastrous Quest for Humaneness."

In 2022, Alabama Gov. Kay Ivey temporarily paused executions and called for an internal review after officials experienced issues inserting an IV in multiple cases.

Factors including dehydration, stress, room temperature and certain illnesses can also make veins more difficult to access. Another problem may be that the person inserting the IV line during an execution lacks experience, Denno, the founding director of the university's Neuroscience and Law Center, told USA TODAY.

"They may not be the person who you and I might go to to have blood drawn who's done this a thousand times, right?" she said. "I mean it may be somebody who is doing much lower level kind of work even though they're a medical professional."

The execution team in Idaho included volunteers who were required to have at least three years of medical experience, according to the state's execution protocols. But their identities are unknown, and Tewalt declined to elaborate Wednesday on exactly what kind of training they've had.

"This is what happens when unknown individuals with unknown training are assigned to carry out an execution," Federal Defender Services of Idaho said in a statement criticizing the attempted execution of Creech.

What's next for Thomas Eugene Creech?

Tewalt said Wednesday that officials would allow Creech's death warrant to expire, and it is unclear when they may attempt to execute Creech again.

"We don't have an idea of timeframes or next steps at this point," Tewalt said. "Those are things we will be discussing in the days ahead."

When asked whether Creech could be executed by another method, Tewalt noted that state statute would have to be changed to allow executions by nitrogen hypoxia, a method used for the first time last month in Alabama.

Though Idaho Gov. Brad Little signed a bill allowing execution by firing squad if that state can't obtain the drugs needed for lethal injection last year, Tewalt said in a statement the Department of Correction is still in the process of trying to retrofit its execution chamber to accommodate a firing squad. 

After the failed execution, Creech's attorneys filed a new request for a stay in federal court, saying “the badly botched execution attempt” proves the department is unable "to carry out a humane and constitutional execution.”

Maher said Creech's lawyers could argue that it would be unconstitutional to put him through the execution process a second time, but it is unclear whether they would be successful. Lawyers representing Kenneth Eugene Smith told the Supreme Court it would be cruel and unusual punishment to try to execute Smith again after a failed lethal injection, but his final appeal was rejected and the state of Alabama executed him in January using nitrogen gas.

Contributing: Emily DeLetter, Maureen Groppe, Jeanine Santucci and Thao Nguyen, USA TODAY; The Associated Press