A federal appeals court Monday pushed Ron Lafferty, who is on Utah’s death row for the 1984 murder of his sister-in-law and niece in American Fork, much closer to a firing squad by denying his latest appeal.

Lafferty, 78, can appeal the latest decision to the U.S. Supreme Court, said Andrew Peterson, assistant solicitor general at the Utah attorney general’s office.

“It’s incredibly unlikely they will review this case," Peterson said, “and if they don’t, we’re talking months” until Lafferty is executed.

Dale Baich, an attorney for Lafferty, issued a statement Monday afternoon.

“When the most severe penalty a state can impose is at stake,” the statement said, “we look to the courts to be the safety net to ensure that the full protections allowed by the Constitution have been met. Here, the court relied on procedural technicalities to deny Mr. Lafferty a complete appellate review of his case.

“We are carefully reviewing the decision and going forward, we will exercise all state and federal legal options.”

(Courtesy of Utah Department of Corrections) Ronald Lafferty, death row inmate.

Utah has not executed an inmate since a firing squad shot Ronnie Lee Gardner to death in 2010. The state has eight inmates on its death row. Monday’s ruling makes Lafferty the closest of them to being executed.

State law gives Lafferty the choice between death by lethal injection or firing squad. Lafferty has said in court proceedings he wants the latter.

In 2004, the Utah Legislature ended the firing squad option, except for inmates who had already been sentenced to die and had selected that method. Then, in 2015, the Legislature added firing squads again, but only if courts determine Utah does not have the cocktail of drugs needed to execute an inmate by lethal injection.

Monday’s ruling by the 10th U.S. Circuit Court of Appeals covered old ground. Lafferty again argued his original trial attorneys misrepresented him, that he should not have been found competent to stand trial and he should not have been made to stand trial a second time after winning an earlier appeal.

Monday’s decision rejected every point. The 18-page ruling from the Denver-based appellate judges repeatedly said they found no errors with the federal and state courts in Utah that already sided against Lafferty’s arguments.

Lafferty and his younger brother Dan Lafferty participated in the murders of Brenda Lafferty, 24, and her 15-month-old daughter, Erica — crimes captured in Jon Krakauer’s book “Under the Banner of Heaven.” According to court documents, the brothers blamed their sister-in-law for helping Ron Lafferty’s wife leave him with their six children. Ron and Dan Lafferty also were upset, according to trial testimony, that Brenda Lafferty opposed her husband, Allen Lafferty, joining their polygamous cult, called School of the Prophets.

On Pioneer Day 1984, Ron and Dan Lafferty forced their way into Brenda and Allen Lafferty’s American Fork duplex. The husband was not home.

(Courtesy photo) Brenda Lafferty

Ron and Dan Lafferty beat her, strangled her with a vacuum cord and slit her throat, court documents say. Dan Lafferty then killed Erica by cutting her throat.

The two brothers were tried separately. Dan Lafferty went on trial first in January 1985. He represented himself. The 12 jurors convicted him of two counts of first-degree murder and four other felonies but were unable to vote unanimously for the death penalty. A judge sentenced him to two life terms.

When Ron Lafferty, who had lawyers representing him, went to trial the following April, the jury convicted him and voted unanimously that he be put to death. The 10th Circuit — the same court that ruled Monday — later overturned the capital murder conviction and ordered a new trial after finding that the wrong standards had been used to evaluate Ron Lafferty’s mental competency.

The second trial commenced in 1996 with the same result — Ron Lafferty was convicted of murder charges and sentenced to die. Lafferty’s legal case has been crawling through state and federal courts ever since.

(Al Hartmann | Tribune file photo) Ron Lafferty

Even if the U.S. Supreme Court rejects the latest appeal, Ron Lafferty will still have some legal options. Once a state judge signs an execution warrant, Ron Lafferty will have the right to request a commutation from the Utah Board of Pardons and Parole.

Peterson said Ron Lafferty’s attorneys might also yet argue he is not competent to be executed. Mental competency has arisen ever since Ron Lafferty was tried the first time, with trial and appellate attorneys arguing he couldn’t adequately assist in his defense.

Peterson said there is a different legal standard for determining if someone is competent to go to an execution chamber.

“As long as he knows why he’s being punished," Peterson said, "he’s competent to be executed.”