'Our innocence was lost.' 1981 South Dakota triple murder approaches 40-year anniversary

Authorities, surviving family disagreed on not guilty verdict

Mathis Home
The home of John Mathis, eight miles north of Mount Vernon, is pictured in this Republic file photo. The farm was the site of a triple homicide nearly 40 years ago. (Chris Huber/Republic)

MOUNT VERNON, S.D. — It was an ugly scene at the Mathis farm outside of Mount Vernon Sept. 8, 1981.

When police were called to the location that night, John W. Mathis was sitting on a bed in the metal shed he and his family were living in after a pair of fires had destroyed their home earlier in the year. His left arm was bleeding from a gunshot wound.

And three members of his family, who resided in this community about 12 miles west of Mitchell, were shot dead.

Mathis told investigators that a man wearing a dark stocking mask had killed his wife, LaDonna Mathis, 30, and two of her three sons, Brian, 4, and Patrick, 2. They had been shot in their beds. LaDonna had been shot twice in the head, Brian had been shot once in the ear and Patrick had been shot in the back of the neck and then in the left eye.

Despite his recounting of the events of that night and claims of innocence, John Mathis was eventually charged with murder. The trial drew interest from around the country. The jury eventually returned a verdict of not guilty, but investigators at the time and after continued to suspect Mathis was the killer.


The story

At about 2 a.m. the night of the killings, Mathis said he had taken Patrick to an outdoor toilet to use the facilities, since the shed in which they were living did not have one of its own. While tending to that task, he said he heard a hog in discomfort and wanted to investigate. He took Patrick back to the shed. The family dog was barking, so he was tying it up when he heard a car.

According to a Mitchell (S.D.) Republic retrospective story from 2011 , Mathis said a masked man then emerged from the shed, where Mathis had left the lights on. He fought with the man and was subsequently shot in the left arm, causing him to pass out. He awoke to find the man gone and his family dead, he said.

The killer, he said, apparently scrawled the words “Mathus sucks” on one of the doors of the shed.

Doug Kirkus, then a deputy with the Davison County Sheriff’s Office and a former high school classmate of Mathis, got a call from him at 3:54 a.m. that night. He told Kirkus that someone had shot his family and to send an ambulance.

Kirkus said the scene at the farm was stunning.

“That was the first time I had ever seen anything of that magnitude,” Kirkus told the Republic in 2011.


The family members were clearly dead, so Kirkus provided first aid to Mathis and later spoke with him at the hospital. As the investigation continued, suspicions began to center on Mathis himself as the probable culprit in the killings.

“That was the first time I had ever seen anything of that magnitude."

— Doug Kirkus, former Davison County deputy

It took some time, but Kirkus said something did not seem right about the version of events Mathis had given the police.

“During the course of the investigation, I can’t tell you how long, some things just weren’t adding up,” Kirkus said.

Tough case

While Mathis was coming into the crosshairs of the case, investigators were dealing with roadblocks to finding the truth.

The three victims had all been shot with a .22-calibre, semi-automatic Marlin rifle using Winchester Western Super X bullets. Law enforcement performed their due diligence in finding out if the shooter had possibly disposed of the weapon somewhere on his property or elsewhere. Deputies searched the farm, but any .22-calibre rifles discovered did not match the weapon that killed the three victims.

Mathis told investigators that he did not even own a .22 rifle.


Mathis Escort
John Mathis, right, is escorted by then-sheriff's deputy Doug Kirkus in this photo from 1981, when Mathis was arrested for the murder of his wife and two sons. A jury later found Mathis not guilty.

Lyle Swenson, then sheriff of Davison County, told the Republic 10 years ago that there was a possibility that Mathis had ditched the weapon in Lake Mitchell, or that an accomplice had helped him dispose of the rifle to cover up the crime. That led investigators to look closer at Vern Mathis, Sr., John Mathis’ father, who Swenson said had long been close to his son.

Despite the missing murder weapon, a Davison County grand jury indicted John Mathis on three counts of murder. In order to bring the case before an unbiased jury, the trial was moved to Yankton County, where the entire state focused its attention as the proceedings got underway.

It was a month-long trial, filled with twists and turns. The fact that investigators found a Winchester Super X shell in Mathis’ pants pocket on the night of the murders was unusual. Mathis said one of his sons had picked up the shell and Mathis had taken it from him, and that similar shells were scattered around.

But one expert witness testified that there wasn’t enough evidence to connect the bullets with the bullets that killed the three victims.
Later at the trial, a member of the jury found a spent Winchester Western Super X shell on the sidewalk, which helped bolster the defense case that finding such a shell on the property was not unusual nor necessarily suspicious.

In regards to the message left on the door of the farm shed, arguments were made that Mathis would not have thought to misspell his own name in an effort to throw off investigators.

The prosecution was led by then-Attorney General Mark Meierhenry, with attorneys Rick Johnson and Wally Eklund, both of Gregory, heading up the defense. The trial continued on for a month. In the end, the jury acquitted Mathis. A lack of prosecution witnesses and a murder weapon that could not be found, coupled with little other physical evidence on hand, gave the jury enough reasonable doubt to not convict him.

“Some man or woman did an unreasonable act, so trying to put calm reason to it ... years later is just impossible."

— Mark Meierhenry, former South Dakota attorney general

The jury foreman for the trial, Gary Monomichl, has said he never doubted the jury came to the right conclusion. The prosecution was also hindered by the fact that they could not convince the jury that a man would harm or kill his own children.

While the prosecution could not secure a conviction, Meierhenry said the case led to child protection reform in South Dakota, with the state Legislature passing laws to protect children and opening the eyes of many citizens of the state to the realities and dangers of child abuse.

Meierhenry told the Republic in 2011 said he respected the verdict, though he did not go on the record on his personal beliefs on Mathis’ guilt or innocence. But he knows a heinous act was committed by someone, and three innocent people lost their lives to an unspeakable crime.

“Some man or woman did an unreasonable act, so trying to put calm reason to it ... years later is just impossible,” Meierhenry said.


While some doubted the jury’s decision, the verdict had been rendered and life began to move on from the crime.

One person who did not doubt the veracity of the jury was Mathis’ son, Duane, who told the Republic he maintained that his father would not have harmed any of his children. The fact that he himself was still alive was testament to that.

“I don’t believe he did it,” Duane Mathis told the Republic in 2011. “If he did, I wouldn’t still be here.”

For all intents and purposes, the case is closed. New evidence would have to emerge, but double-jeopardy and other laws would make it difficult to restart the process. The statute of limitations has expired on many of the potential charges.

A few boxes of evidence in the case were handed over to the South Dakota Division of Criminal Investigation Cold Case Unit, but a message from the Republic to the South Dakota Attorney General’s office about whether a cold case investigation had been conducted or was underway was not returned.

The case remains an example to the savagery of human beings, regardless of who committed the murders, Meierhenry said. The impact and infamy of the murders and trial years later shows that the crime affected not only the victims, their family and those who worked to prosecute and defend Mathis, but also the residents of Davison County and South Dakota itself, cannot be overstated, Meierhenry said.

“Our innocence was lost,” he said.

Erik Kaufman joined the Mitchell Republic in July of 2019 as an education and features reporter. He grew up in Freeman, S.D., graduating from Freeman High School. He graduated from the University of South Dakota in 1999 with a major in English and a minor in computer science. He can be reached at
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