"Department officials have said all four drugs were purchased in the United States, but declined to say how the drugs were obtained or who provided them. They're currently fighting lawsuits by the American Civil Liberties Union of Nebraska and Nebraska media outlets that could force them to release documents identifying the supplier. Nebraska's last execution was in 1997, using the electric chair, but the state Supreme Court later declared the chair unconstitutional."
New York Times
July 27, 2018