CHEYENNE, Wyo. — A judge in Wyoming sentenced a 75-year-old Missouri woman to life in prison on Monday for killing her husband with a rifle in the mid-1970s and throwing his body down the shaft of an abandoned gold mine, where it remained for nearly 40 years.

Defendant Alice Uden wore wire glasses, a court-supplied hearing aid and a blue suit, and sat quietly in her wheelchair before speaking at the hearing.

She sobbed gently as she addressed the court about the death of her third husband, Ronald Holtz, then 25.

“I’ve tried to atone for it,” Uden said. “I wish that I never would have met him so that none of this ever would have happened. He was a very frightening man.”

Jurors in Cheyenne didn’t buy Uden’s argument that she shot Holtz in the head to defend her toddler daughter from him. In May, they found her guilty of second-degree murder.

Uden killed Holtz in late 1974 or early 1975 in Cheyenne, where he was living with her and her 2-year-old daughter. Uden testified that she shot him with a rifle after he flew into a rage over the girl’s crying and was inches away from attacking her in bed.

Laramie County District Court Judge Steven Sharpe said he considered possible mitigating factors, including Uden’s lack of prior criminal history.

“This was very much a cold, calculated murder,” Sharpe said. “The jury heard all of the evidence that was before the court and the jury rejected the defense that it was self-defense.”

District Attorney Scott Homar argued the killing was a thoughtful, deliberate act that rid Uden of Holtz.

“Her way out was to take Mr. Holtz’s life while he was sleeping and then dispose of it in a way that it wouldn’t be found for 39 1/2 years,” Homar said.

Police arrested Uden and her fourth and current husband, Gerald Uden, 72, both of Chadwick, Missouri, last fall in southwest Missouri, accusing them of killing former spouses in separate attacks.

Gerald Uden is serving a life sentence after he pleaded guilty to killing his ex-wife and her two sons in central Wyoming in 1980. Prosecutors have not drawn any link between the two cases.

At her trial, Alice Uden testified that she removed Christmas decorations from a large cardboard barrel and put Holtz’s body inside. She wrestled the barrel into her trunk, she said, and dumped the barrel in an abandoned gold mine on a ranch between Cheyenne and Laramie.

One of Uden’s sons, Todd Scott, testified at the trial that his mother told him decades ago that she had shot Holtz while he was asleep.

After previous, unsuccessful attempts to find Holtz’s remains in the mine filled with the carcasses of cattle and other ranch animals, investigators last summer dug deeper in the vertical shaft and finally excavated Holtz’s remains.

The jury declined to find Uden guilty of premeditated, first-degree murder, which would have carried a mandatory life sentence. The jury also declined to convict her of a less-serious charge of manslaughter.

Uden’s attorney, Donald Miller, urged the judge to sentence Uden to probation because the now-grown daughter, Erica Prunty, has cancer and has been given six months to live.

He also highlighted the psychiatric history of Holtz, who met Uden, a former nurse, while she was working in the psychiatric unit at a Veterans Administration hospital in Sheridan.

“His behavior was unpredictable. He was irritable, he was hostile, he was explosive. He had no incentive to change,” Miller told the courtroom.

Prosecutors in the case against Gerald Uden said the bodies of 32-year-old Virginia Uden, and her two sons, 11-year-old Richard Uden and 10-year-old Reagan Uden, have yet to be found.

Gerald Uden told a Fremont County courtroom in November that he shot each of them with a rifle not far from his home, one after the other, and dumped their bodies in an abandoned mine.

Months later, he said, he retrieved the bodies and sank them in Fremont Lake in western Wyoming. Investigators briefly searched the deep lake for the bodies and say they plan a more comprehensive search soon.

Jurors at Alice Uden’s trial were prohibited from hearing about Gerald Uden’s case.