A killer who has spent the last 30 years on Nebraska's death row died in prison on Sunday. Michael Ryan, awaiting execution for the 1985 cult killings of two people, including a 5-year-old boy, died around 5:45 p.m. local time at the Tecumseh State Correctional Institutional in southeast Nebraska, the Nebraska Department of Correctional Services said in a news release Monday, according to the Associated Press. Tecumseh prison spokeswoman Jessica Houseman said an autopsy would be performed.

The exact cause of death was not released, but at a hearing in March to discuss the repeal of state legislature regarding the death penalty, state Sen. Ernie Chambers said Ryan had terminal brain cancer. Houseman did say that Ryan was being treated for a long-term medical condition.

Ryan was convicted of killing 26-year-old cult member James Thimm at a farm in southeast Nebraska near Rulo, where Ryan led the cult. Over the course of three days, Thimm was beaten, sexually abused, shot, partially skinned while still alive and stomped. His fingertips had been shot off on one hand, according to NBC News. Ryan was also convicted for the beating death of the 5-year-old son of a cult member.

Ryan told his cult followers that he heard the voice of God and that Thimm had angered God. Ryan has been on death row since Sept. 12, 1985. Ryan's son, Dennis Ryan, and fellow cult member Timothy Haverkamp were sentenced to life in prison for second-degree murder in Thimm's death.

Dennis Ryan delivered the gunshot that finally killed Thimm after days of torture, authorities said, according to NBC News. Dennis Ryan won a new trial, was convicted of manslaughter - a lesser charge - and has since been released from prison. Haverkamp has been out of prison since 2009 after serving 23 years of a 10-years-to-life sentence.

Nebraska had no means to execute Michael Ryan since one of the three drugs needed to execute him had expired, according to the Associated Press. On May 14, Gov. Pete Ricketts announced that state officials had obtained all three drugs required for executions, but less than a week later, the legislature gave final approval to abolish the death penalty in Nebraska. The governor has said he plans to veto the bill on Tuesday.