Nebraska’s first lethal injection could be stalled after a German pharmaceutical company filed a lawsuit this week in federal court saying the state may have illegally obtained an untested four-drug lethal cocktail.

The case is the latest in what a national death-penalty expert told the media was a setup for a showdown, which included a New Jersey-based drug company Alvogen’s effort to block the use of its sedative midazolam in the stalled execution of Scott Raymond Dozier in Nevada. Documents filed with the Nevada Supreme Court say that drug company Alvogen’s effort to block the use of its sedative midazolam in Nevada is part of a “guerrilla war against the death penalty.”

The German company, Fresenius Kabi, alleges that Nebraska was planning to use two of its drugs for a lethal injection to kill Carey Dean Moore next week. In 1979, Moore was sentenced to death for murdering two taxi drivers in Omaha.

Moore is not contesting his sentence. But the German company’s lawsuit could tie up his death sentence as the case moves through the legal system.

Fresenius Kabi said that the state may have illegally obtained the drugs because the company opposes the use of its products in executions. The company has all those who buy its drugs sign an agreement that they will not sell them to correctional institutions.

Capital punishment is not only illegal in the European Union, but is widely unpopular among many voters and viewed as a grotesque human rights violation. The German firm alleged that the large drug company could suffer “great reputational injury” if its drugs are used for the death penalty.

Nebraska planned to use a mix of the narcotic painkiller fentanyl citrate, the sedative Diazepam, the muscle relaxer cisatracurium and potassium chloride, a drug that stops the heart.

Fresenius Kabi suspects it is the source of the last two drugs. The company is asking a federal judge to issue an order either temporarily or permanently blocking the state from using the injectable mix.

The state has not disclosed its source of the drugs. The issue has become a problem for states that continue to carry out the death penalty through lethal injection.

“Nebraska’s lethal injection drugs were purchased lawfully and pursuant to the state of Nebraska’s duty to carry out lawful capital sentences,” the state attorney general’s office said in a short statement.

Injectable drugs have become difficult to obtain due to several drug manufacturers’ refusal to sell their products to prisons for use in executions.

Last month, multinational pharmaceutical company Alvogen accused the heads of Nevada’s prisons of working to illegally buy one of its drugs to use in an execution of Dozier, who was convicted in 2007 of robbing, killing and dismembering a 22-year-old man in Las Vegas. He was also convicted in Arizona in 2005 of another murder and dismemberment near Phoenix.

A federal judge called a hearing just hours before the killing was due to take place to listen to a demand by the drug manufacturer Alvogen for a block on the use of its sedative, midazolam, in putting to death Dozier.

“The families of these victims deserve justice,” Arkansas’ state Attorney General Leslie Rutledge said in a statement last week. Arkansas is leading the 15 states that siding with Nevada according to the Associated Press, including Alabama, Arizona, Florida, Georgia, Idaho, Indiana, Louisiana, Missouri, Nebraska, Oklahoma, South Carolina, Tennessee, Texas and Utah.

Documents filed with the Nevada Supreme Court say that drug company Alvogen’s effort to block the use of its sedative midazolam in the stalled execution of Dozier in Nevada is part of a “guerrilla war against the death penalty.”

At the same time, around the world capital punishment has become increasingly unpopular. For example, Pope Francis changed Catholic Church teaching to fully reject the death penalty, the Vatican announced last week.

The pope pledged to work to abolish the death penalty worldwide. His announcement also re-energized a debate over what antiabortion means in the United States. The church’s updated teaching describes capital punishment as an assault on the “dignity of the person.”

Texas Gov. Greg Abbott, a Catholic, presides over the state that carries out the highest number of executions. But several states have opened fresh discussions about abolishing the punishment amid the antiabortion debate.