LINCOLN, Neb. (AP) — The ACLU of Nebraska is investigating the state’s purchase of new lethal injection drugs to carry out executions.

The civil liberties group filed an open records request Friday to review whether the acquisition was lawful.

Gov. Pete Ricketts announced Thursday that state officials have bought all three drugs required for executions. Nebraska lost its ability to execute prisoners when its supply of sodium thiopental, a required lethal injection drug, expired in December 2013.

ACLU of Nebraska executive director Danielle Conrad says the state has faced legal problems in its past efforts to obtain lethal injection drugs, and her group will hold officials accountable.

Nebraska Solicitor General Jim Smith, who handled previous death penalty cases, has said the issues raised in past cases were later resolved.