Cold case review in decades-old murder case leads to Willmar native

Sioux Falls, South Dakota, resident Algene Leeland Vossen, 79, is awaiting trial for murder after a Willmar Police Department cold case review team zeroed in on him in 2020. A Willmar native, Vossen is charged in the January 1974 homicide of Mabel “Mae” Agnes Herman, 73, of Willmar, Minnesota.

Algene Leeland Vossen Photo via Minnehaha County (S.D.) Jail

WILLMAR — Mabel “Mae” Agnes Herman was 73 on Jan. 26, 1974. She was part of a sewing circle and a member of the Vinje Lutheran Church in Willmar.

Her grandson, Andrew Herman, said he had heard from his dad, Mae Herman’ s only child, that she was a kind person and that she meant a lot to his father, though he didn’t talk about her much.

Mabel Herman last spoke to her sister at 11 a.m. that day. A newspaper boy saw her a couple of hours later letting her cat out. Less than 32 hours later, Willmar Police Department officers would be in her Willmar home, looking at her body riddled with stab wounds.

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Andrew Herman said he wasn’t aware of what had happened to his grandmother until his dad, John Herman, sat him and his sister down for a talk prior to the airing of an unsolved crime TV show when Andrew was about 10.


“After he had told us (that she was killed), it kind of made sense,” Andrew said in a July 2020 interview, adding that he was sure it was still traumatic for his father even years later to have lost his mother like that. “I think it was hard for him to talk about his mother.”

Mae Herman was killed a year before her grandson was born and Andrew Herman’s older sister was about 2 at the time.

Related: Mabel Herman homicide story list

“So we pretty much grew up without a grandmother,” he said.

What exactly happened during that time is only truly known by her killer. Crime scene photos show a newspaper dated Jan. 26, 1974, that sits on an ottoman and appears to have been read. The floral drapes are pulled back with the blinds pulled down. Her phone has been ripped out of the wall. No furniture is tipped over and the house looks lived in.

In the middle of this lies Herman on her living room throw rug. Her left foot underneath a chair where a portion of a newspaper and a hairbrush sits, her hair and glasses disheveled with her shoes next to her right foot. She is wearing a blood-soaked sweater that would play a major role decades later.

It doesn’t appear there was much of a struggle across the house, though Herman’s body shows multiple violent wounds across her stomach, chest and neck. No weapon has ever been found.


Mabel "Mae" Agnes Boyer Herman's body is removed from her home at 804 West Sixth Street by Willmar police officers Sanford Larson and Roger Klinghagen. Herman was found dead in her home on Jan. 27, 1974. Willmar police have made an arrest in the homicide that had remained unsolved for 46 years. Mike Gunter / West Central Tribune file photo

Read more about the criminal complaint here.

Any homicide would trouble people in Willmar, even today, but an elderly woman being so brutally killed in her home sent shock waves through the city and Kandiyohi County.

“It wasn’t a personal fear that some guy was going to jump out of the bushes and stab me,” said Brad Koenig, 65, who went to Ridgewater College at the time, in a July 2020 interview. “Because it was an elderly woman, I think it was more disgust and shock that something like this could happen in Willmar.”

A crime scene photo of Mabel Herman's phone. The cord has been ripped out of the wall. File photo / West Central Tribune

Algene Leeland Vossen , 79, is awaiting trial for murder after a cold case review team zeroed in on him in 2020. Vossen, whose defense attorney paints him as a frail old man, is currently in Iowa awaiting medical treatment.

Who is Algene Vossen?

Vossen was well-known in Willmar at the time of Herman’s killing. A known peeping Tom, he almost instantly became a suspect.


Algene Vossen mug.jpg
Algene Leeland Vossen

"(Vossen) was a bum," said Mike Gunter, 72, a former West Central Tribune photographer, in a July 2020 interview. Gunter was also the primary crime scene photographer for the Willmar Police Department at the time of the killing.

"He'd been into a lot of trouble, petty thefts, et cetera," said Gunter.

According to the Minnesota Department of Corrections, Vossen had three state prison stretches from 1963 to 1973, including a three-year sentence for grand larceny in Traverse County, a five-year sentence for burglary in Kandiyohi County and a three-year sentence for attempted burglary in Kandiyohi County, though Vossen was paroled a little after one year for the attempted burglary.

Discovery documents submitted by the Kandiyohi County Attorney’s Office in September 2020 list police reports of an October 1966 window peeping incident, a September 1970 assault, a January 1974 obscene phone call and a February 1974 window peeping incident.

Vossen was stopped in February 1974 by the Willmar Police Department for a window peeping incident when he had told officers he picks his houses at random and had no special desire for older women.

A crime scene photo of Mabel Herman's front door.

During the interview, Vossen said that since his release from Stillwater prison in May of 1973, he had been window peeping on multiple occasions. Vossen admitted he needed mental help, according to the narrative in the criminal complaint for Vossen’s arrest in Herman's killing.


Vossen was also questioned about Herman’s death during that interview, something he said he didn’t know much about and said he was bar hopping that night. An alibi that his then-girlfriend, Lydia Olson, backed up at the time.

Vossen and Olson would later marry in October 1974 in Iowa. She died in May of 2020 in Sioux Falls, South Dakota.

While in Iowa, Vossen racked up dozens of criminal cases, ranging from drunkenly fighting cops to making obscene phone calls and indecent exposure in the Polk County area, including a September 1981 incident when Vossen was arrested and convicted of five charges related to an incident at the home of the then-Polk County Treasurer Fred Horner.

According to law enforcement records, Vossen was accused of looking into the Horner residence’s windows at Beth Horner, Fred’s wife, leaving and then making obscene phone calls to her.

The list of infractions is extensive.

In April 1979, Vossen was convicted of making harassing phone calls to a residence in Johnston, Iowa.

In November 1979, Vossen was convicted of trespassing on multiple properties in Urbandale, Iowa, and convicted of indecent exposure “by exposing his genitals to masturbate,” according to law enforcement records.

In November 1982, Vossen was convicted of “window peeking” and public intoxication in Des Moines, Iowa.


In March of 1983, Vossen was convicted of criminal trespass and harassment at an address in Des Moines which included Vossen making 17 phone calls of an obscene nature to a residence.

Vossen was sentenced to 30 days in jail for this offense and ordered to report to a hospital for treatment. Most of Vossen’s convictions in Iowa included fines ranging from $25 to $100 or two to five days in jail.

Vossen and his wife would later move in 1993 to Sioux Falls where he picked up two driving under the influence charges, adding to at least one driving under the influence conviction in Iowa.

Vossen was arrested for the Herman homicide on July 23, 2020, at his Sioux Falls home by members of the South Dakota Division of Criminal Investigation, the Sioux Falls Police Department and Willmar police officers.

Read more about Vossen’s criminal history here.

Case reports dating back to the mid-1970s were read by the Willmar Police Department Cold Case Review Team to help determine the primary suspect in the 1974 killing of Mabel "Mae" Agnes Boyer Herman this past July. Erica Dischino / West Central Tribune file photo

The investigation

Willmar’s police chief at the time of Herman’s death, Lyle Goeddertz, told the West Central Tribune in April of 1974 the investigation had hit a brick wall.


Vossen had been questioned during a Feb. 16, 1974, stop for a window peeping incident. He told investigators that he did not know Herman and didn't know anything about the case other than town talk and what was said in the newspaper and on the radio.

Vossen said he had been bar hopping in Willmar the nights of Jan. 26 and Jan. 27 in 1974 and that he and his then-girlfriend, Lydia Olson, usually went to John's Supper Club and then the Veterans of Foreign Wars post and/or the American Legion in Willmar.

Olson, who did clerical work at the West Central Tribune at the time, told an investigator on May 20, 1974, that Vossen came home around 9 p.m. Jan. 26, about an hour and a half later than he usually came home, as they always had supper at 7:30 p.m.

She said that Vossen had been drinking but was not drunk.

The department never did follow-up interviews with bartenders where Vossen said he had been.

Glenn Negen, 73, had been on the Willmar police force for just six months when Herman's body was found.

Negen, who died in October of 2020, said in a July 2020 interview he played a minor role in the investigation, mainly guarding the Herman house so police didn't have to get another search warrant, but that there was some urgency within the department to catch the killer.

"The concern was the unknown part: Do we have a murderer in our presence and is he going to do it again?" Negen said.

A crime scene photo of a foot print around Mabel Herman's home.

On Dec. 21, 1979, an investigator traveled to Des Moines to meet with Vossen at a Denny's restaurant.

According to the complaint, Vossen immediately wanted to know what was going on and was "obviously nervous and distrustful (of the investigator)."

The investigator indicated he was not going to arrest Vossen but wanted to talk with him about the homicide, mentioning that the department had a psychologist who was interviewing witnesses and suspects in the case.

Vossen declined to travel to Willmar from Iowa for an interview with the psychologist, citing work obligations.

According to the complaint, Vossen told the investigator "there was no way in hell that he was going to Minnesota or was going to talk further about the case" and that police would need to get a warrant for his arrest if they wanted to talk with him further.

Vossen then wanted to know about any evidence in the case that made the officer travel to Iowa to speak with him. The investigator declined to discuss details, saying it would be "bad police work" to do so.

The investigator noted that Vossen was "quite excited" during the interview, talking fast, visibly shaken and mixing up his words.

The investigator also noted that Vossen's main concern seemed to be what new evidence the police had uncovered in the homicide investigation regarding him, according to the complaint.

"I know they interrogated him pretty heavily," Gunter said. "They really thought that he was probably the culprit, but I just don't think they had enough evidence that they could put the last nail on the board."

That nail on the board would come during a cold case review by the Willmar Police Department in 2020.

"When I became chief, I knew that this Mae Herman case was unsolved and we had been talking as a group at some of our strategic planning meetings that, at some time, when we had enough personnel and enough time, we wanted to get people together and do a cold case review," Willmar Police Chief Jim Felt said in a August 2020 interview. "That Mae Herman case was probably the primary one."

Over a two-week period, the cold case team, gathered in the department's meeting room, looked over the evidence in the case, including some well-preserved physical evidence and hundreds of documents.

A crime scene photo of Mabel Herman's door.

The team narrowed in on Vossen because of statements Vossen made during the initial investigation and his penchant for window peeping.

"Initially, they had a different suspect that they were looking into pretty seriously, and then when Vossen came around, the evidence just kind of built up and built up and built up," Willmar Officer Jason Evans said in a August 2020 interview. "The more we read, the more information that came in on him, the first suspect kind of melted away."

While Vossen was of interest, the team relied on DNA evidence to officially eliminate people as suspects.

DNA analysis was more primitive in 1974, according to Willmar Police Sgt. Chad Nelson in a August 2020 interview, with officers needing a lot of blood to basically get a blood type match.

In 2020, DNA analysis has advanced to the point at which, with enough evidence, law enforcement is able to match it to specific people.

Nelson said they had DNA samples from other suspects in the case sent to the Minnesota Bureau of Criminal Apprehension crime lab along with Herman's sweater and pants.

"Fortunately enough, we were able to eliminate two suspects right off the bat when they found blood from an unidentified male on her sweater," Nelson said.

With the assistance of the South Dakota Division of Criminal Investigation, the team was able to secure and serve a search warrant for Vossen's DNA at his home in Sioux Falls on July 7. A brief interview also took place and Vossen stuck to his previous statements.

On July 17, two saliva swabs were all it took for the BCA crime lab to confirm Vossen's DNA was the same DNA found on Herman's sweater.

Felt said when he got a notification that the BCA crime lab had results, he couldn't get logged in fast enough.

"When I pulled up the results and printed it out, Sgt. Nelson was on a vacation day and I thought he would not mind me calling him on a day off to let him know the results are there," Felt said.

A crime scene photo of a stain on a surface in Mabel Herman's house.

While there's an obvious sense of excitement with being able to finally charge someone, Nelson remains cautious as the wheels of justice turn.

"For me, Vossen is innocent until proven guilty," Nelson said. "It's a step and it's moving forward, but the case isn't done until he's back here and he goes to trial or pleads guilty or he's found not guilty."

When Negen heard the news that Vossen was arrested, he said he was ecstatic.

"It was exhilarating," Negen said. "Really, really happy to hear."

Read more about the Willmar Police Department's cold case team here.

Algene Leeland Vossen Photo via Minnehaha County (S.D.) Jail

Pretrial proceedings

Vossen is an old man now. He has medical and mental issues. He was originally extradited from South Dakota to the Kandiyohi County Jail to face second-degree murder charges but was released on medical furlough in October of 2020 to seek treatment for his ailments, including dementia.

He is currently in the care of his niece, Janette Sanders, in her Des Moines, Iowa, home where he is under house arrest.

His attorney, Kent Marshall, has argued in court that Vossen’s mental state is a barrier to a proper defense.

In a Nov. 2, 2020, motion to the court, Marshall said he believes Vossen suffers from dementia “that prohibits him from entering into meaningful discussions with his attorney for purposes of preparing for trial” as well as “various extreme physical disabilities and illnesses that make it virtually impossible for him to assist me, as his defense counsel.”

Documents: Court documents and correspondence in the Algene Leeland Vossen homicide case

Vossen has often appeared in court, via Zoom, bedridden, and was recently ordered to undergo a competency evaluation though Assistant Kandiyohi County Attorney Kristen Pierce argued to deny that motion because Marshall did not provide specific instances of cognitive decline in Vossen that would require an evaluation.

Eighth Judicial District Judge Stephen Wentzell said in court that if there's reason to doubt the competency of a defendant, the court has to order a competency evaluation by a forensic psychologist.

"In this case, Mr. Marshall indicates and represents to the court that he has concerns regarding Mr. Vossen's ability to meaningfully consult with him," Judge Wentzell said during the Jan. 4 hearing.

Vossen’s review hearing won’t be until April 12 and even then, this story won’t have an ending. As the court proceedings go on, the Herman family and the city of Willmar will wait to see how justice unfolds.

Gallery: Mae Herman case file photos A gallery of crime scene photos at Mae Herman

Mark Wasson has been a public safety reporter with Post Bulletin since May 2022. Previously, he worked as a general assignment reporter in the southwest metro and as a public safety reporter in Willmar, Minn. Readers can reach Mark at
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