A week before Christopher Sepulvado is scheduled to be put to death for killing his stepson, lawyers pursued two tracks to delay the execution based on the drugs the state will use to carry out his sentence.

A brief, filed with the U.S. Supreme Court on Tuesday, argues that the pending execution could amount to “human experimentation” because of secrecy regarding the state’s execution protocol.

“The recent unavailability of drugs previously used in lethal injection has triggered a new chapter in lethal injection experimentation that should be halted,” wrote lawyers for the Roderick and Solange MacArthur Justice Center in New Orleans on behalf of three medical experts.

That brief was filed a day after Sepulvado’s lawyers asked the U.S. Supreme Court and the state to delay the execution.

The other motion, filed Tuesday with the U.S. District Court for the Middle District of Louisiana, asks a judge to sanction state officials and delay the execution because the Department of Corrections has withheld important documents and suddenly added a new drug option nine days before the Feb. 5 execution.

“While the Defendants did produce some 1500 pages of documents by that date, the produced documents make clear the existence of other — withheld — responsive documents that are material to this civil rights action,” Michael Rubenstein wrote.

The state’s responses to the plaintiff’s questions “reveal bad faith and evasiveness especially in light of newly disclosed information about critical aspects of the execution protocol,” Rubenstein wrote.

The Supreme Court brief points to a recent Ohio execution in which convicted rapist and killer Dennis McGuire reportedly gasped and snorted for fifteen minutes before succumbing to a concoction of the sedative midazolam and the painkiller hydromorphone.

That was the first time those two drugs had been used for lethal injection in the United States. Monday, the Louisiana Department of Corrections changed its rules to allow those drugs to be used in an execution.

The lawyers argue in the Supreme Court brief that before McGuire’s execution, a state expert admitted that he did not know how long it would take for the inmate to stop breathing when he was injected with the drugs, saying there was “no science” to the process.

Louisiana changed its rules to allow for the two-drug combination after its supply of another execution drug, pentobarbital, expired and it couldn’t find any more.

Other states have scrambled to find new ways to execute prisoners after manufacturers banned their use in executions and the supply of drugs expired. Some states have turned to compounding pharmacies, which mix or alter drugs for special cases.

The Louisiana Department of Corrections has talked with one of those pharmacies, The Apothecary Shoppe in Tulsa, Okla., about supplying pentobarbital. But that would have been illegal because the pharmacy isn’t licensed in Louisiana.

Meanwhile, a lawyer continued to challenge the state’s secrecy regarding how it plans to execute Sepulvado, whose death sentence has been delayed several times. He was convicted in 1993 for beating his 6-year-old stepson with a screwdriver and then holding him down in scalding water.

Rubenstein’s motion, submitted on behalf of Sepulvado and inmate Jessie Hoffman, contends that the state has withheld important documents related to the inmates’ lawsuit, which seeks to know exactly how they will be executed.

Rubenstein noted that on Friday, a lawyer for the Department of Corrections said the state was still “in the process of procuring” pentobarbital for Sepulvado’s upcoming execution.

Monday evening, Pam Laborde, the communications director for the Department of Corrections, announced that the state had added the two-drug option used in Ohio because officials couldn’t find pentobarbital.

Rubenstein wrote that the change amounted to a “wholesale transformation” of the execution plan. “It is clear that such changes were in the works for some time and were not made suddenly on the very evening they were disclosed,” he wrote.

He also questioned a statement in an Oct. 1 legal filing by the state, which said “as of September 2013 there is an adequate supply of viable pentobarbital for use in executions by lethal injection as of this date.”

But documents supplied by the state on Friday show that officials knew the drug would expire in September and were looking for other options, Rubenstein wrote.

Laborde and James Hilburn, a lawyer for the Department of Corrections, did not immediately return requests for comment.