Diane Olkwitz was stabbed more than 100 times in a Wisconsin factory on Nov. 3, 1966. Her killer has never been caught.
Fifty-three years later, family members cling to the hope that her murder will be solved.
Diane, 19, was a secretary at Kenworth Manufacturing Co. in Menomonee Falls, which was a metal stamping plant. She had worked there since graduating from high school 18 months earlier.
Kenworth employed 25 factory workers, whose weekday shifts ended at 3:30 p.m. Diane, the only secretary, remained alone until 4:30 every afternoon to answer calls and accept late deliveries. After work, Diane would pick up her best friend, Diane Zimmer, at her nearby workplace and the two would drive home together.
On Nov. 3, Diane was late picking up Zimmer. Concerned, Zimmer accepted a ride with her employer’s wife, who offered to take her to Kenworth. There, they found Diane’s car in the parking lot. Peering through a window of the plant, they saw Diane’s purse on a desk and her coat hanging near the closet, but no sign of Diane. All the doors were locked.
Unsure of what to do, the pair walked to the plant next door, where Diane’s brother Dennis worked. The three returned to Kenworth just as a supervisor arrived to do some after-hours work. It was 5:20 p.m. when the supervisor unlocked the shipping room door.
The four of them discovered Diane lying about 20 feet away, face down in a pool of blood.
One of six children
Diane was the second daughter in a busy Catholic family of six children. She had two older brothers, Dennis and Edward, and three sisters, Nancy, the eldest, and Patti and Debi, both younger.
“She was a very warm and caring person,” said Debi Olkwitz, who was just 9 when her sister was murdered. “Always looking out for other people. She was just a generous person that way.”
Diane’s sister Patti Saidler, who was four years younger, remembers her as sensitive but outgoing. “We were very close,” she said. “She was pretty much my mentor.”
The family lived down the block from St. Mary Catholic Church, where they were parishioners.
Zimmer had known Diane since elementary school, but it wasn’t until freshman year that the two became close.
“She was a very special girl,” Zimmer said. “Sweet and quiet. She was a perfect friend.”
By the time Diane finished high school, she had matured into a tall, slender brunette with a quick wit and bright smile.
“She was such a delight,” Patti said. “She had the greatest sense of humor. She was really a beautiful girl.”
Diane visited St. Mary’s regularly to seek answers to problems.
“She would take everything to church,” Patti said. “If she was struggling with something, she’d run up to St. Mary’s and she would pray about it.”
Though Diane dated in high school, and even went steady with a couple of boys, she didn’t get serious until shortly after graduating when she met Donald Hierlmeier from Milwaukee. Eventually, the couple would become engaged.
That summer, Diane found her secretarial job at Kenworth Manufacturing. After working for a year, she decided it was time to move out of the family home and rented an apartment with her brother Edward’s girlfriend. In September, she served as maid of honor at Zimmer’s wedding. Zimmer married her longtime high school sweetheart.
Shortly after, Hierlmeier, who had been drafted into the Army, left for basic training at Fort Hood, Texas.
Lonely without him, Diane signed up for swimming and knitting classes in the evenings and took a part-time job as a hostess at the local Dutchland Dairy restaurant to fill the hours. She was scheduled to work the day she was killed.
On the afternoon of Diane’s murder, Patti remembers calling her big sister hoping to borrow a blue mohair sweater for a sleepover that night. Diane gladly obliged, saying she’d leave it outside her apartment door.
“Growing up having her as a sister was really special,” Patti said. “And not having her around was really, really difficult.”
Multiple stab wounds
Diane died of massive hemorrhaging due to multiple stab wounds to the chest, neck and head, according to James Welch, the Waukesha County coroner at the time.
She had been stabbed 106 times with a knife that likely had a 3½-inch blade with one cutting edge.
The wounds measured from one-half to three-quarters of an inch wide and from 2¼ to 3¾ inches deep.
She had at least 30 stab wounds in her head, neck and face, and 35 in rows down the sides of her back, where she had been stabbed repeatedly while on her stomach.
There were defensive wounds on her arms and the back of her hands. Her nose had been broken.
Diane was found with her knit dress pulled up between her legs and partly off her shoulders but her undergarments undisturbed. She had not been sexually assaulted, Welch determined.
First murder in the village
Diane’s murder stunned what was then the sleepy village of Menomonee Falls.
Officials there said it was the first murder they could recall in the tranquil community just outside Milwaukee’s northwestern city limits.
In 1966, the village was a lot more insulated than it is today. The big-city crime of Milwaukee did not encroach on the idyllic hamlet where children played outside unsupervised past dark and nobody locked their doors.
Two months before Diane’s death, a 10-year-old girl was found sexually assaulted, stabbed and beaten to death in Milwaukee. Debi Olkwitz recalls seeing it on the news and the fear she felt because they were close in age.
“I remember talking to Diane about it,” she said. “And I remember saying, ‘It’s so scary that that girl got murdered’ and Diane said, ‘Oh, you don’t need to worry, we’re fine, we live in Menomonee Falls.’ ”
In the days after Diane’s murder, with the killer still at large, sales of large dogs, chain locks and firearms all increased as residents began to question how safe they really were.
A funeral Mass at St. Mary’s was attended by 250 people, including Hierlmeier, her grief-stricken fiancé, who had been granted emergency leave from basic training and was still in a state of shock over the tragic news.
During the Mass, St. Mary’s pastor implored the killer to turn himself in and asked those in attendance to pray for him.
Friends, acquaintances questioned
Police wasted no time in their effort to catch Diane’s killer, rounding up and interviewing dozens of friends and acquaintances the very night of the murder.
It was the first year on the job for Patrolman Dan Schramm, who would retire 26 years later as a captain before going on to serve as a village alderman. He remembers that night well.
“The evening of the homicide I was assigned to remain in the building overnight to observe any comings and goings,” he said.
Detectives had hoped the killer might return to the scene of the crime. Nothing happened.
Still, Schramm recalled, “It was an eerie feeling.”
Police theorized the killer surprised Diane as she was leaving for the day. They also speculated the killer was familiar with the plant’s layout and may have known she would be alone at that hour.
Then-Menomonee Falls Police Chief Charles Kuhn said he believed that Diane knew her killer.
Seven detectives worked 12- to 16-hour shifts with no days off trying to solve the crime.
More than 100 pieces of evidence were sent to the FBI in Washington, D.C., for analysis, including fingerprints lifted at the scene and Diane’s bloody clothing.
Over the weeks that followed, police interviewed more than 500 people and came up with what they thought were six strong suspects. All had alibis.
Diane’s family and close friends pointed police toward one person in particular, her employer’s son, whose unwanted advances had frightened Diane.
“She was terrified of him,” her sister Patti said. “He obviously was attracted to her and had been bugging her to go out with him. And she just didn’t want anything to do with him.”
Police questioned the employer’s son extensively, but he had an alibi as well. He said he had been with family members at the time of the killing. His family backed him up.
It wasn’t long before leads began to dry up. The evidence sent to the FBI didn’t result in any break in the case. Police were forced to move on to other crimes.
Weeks turned to months and months to years, and Diane’s unsolved murder hung like a dark cloud over the department.
“The case was always on the minds of anybody who worked there,” Schramm said.
DNA profile created
The advent of DNA technology in the 1990s gave Diane’s family and police renewed hope her case could be solved.
A DNA profile was created from evidence found at the crime scene and entered into CODIS, the FBI’s Combined DNA Index System that looks for matches with convicted offenders.
Despite the millions of profiles in CODIS, a match was not obtained.
Police tracked down early suspects to gather DNA samples, but again there were no matches.
The one suspect they were most interested in getting a sample from — the employer’s son — had died in 1991. Despite his alibi, his obsession with Diane had always made him the prime suspect in the eyes of the police. Unfortunately, his body had been cremated and the whereabouts of his remains were unknown.
Police sought and received a court order to exhume the bodies of his parents to obtain DNA samples for comparison with the crime scene profile. Again there was no match.
With no new leads and no other suspects from which to obtain DNA, police were back to square one.
Today, there are nearly 3,000 pages of documentation related to Diane’s case. The reports and associated paperwork pack three file boxes at the Menomonee Falls Police Department and have also been scanned into an electronic database for easier access.
Lt. Steve Rudie, who heads the department’s special investigations bureau, says that despite the passage of time Diane’s case remains an active investigation.
“We are pursuing every lead that presents itself to us even at this date 50 years later.”
Tips continue to trickle in. As they do, Rudie said the department follows them up, interviewing suspects and persons of interest and obtaining DNA samples. To date, there have been no matches, either from new leads or CODIS.
Rudie said although DNA is a useful tool in investigations, it is not without its limitations.
“A DNA match would assign a name to the person that left that material behind. It doesn’t make that person the killer nor does it absolve any of the non-matches,” he said.
Rudie said the department continues to monitor evolving DNA technology in an effort to crack the case. As new technology comes up “we will make use of it,” he said.
Police believe, as they have from the beginning, that Diane knew her killer.
“When you have a crime with this level of violence it is often a very personal and interpersonal relationship between the killer and the victim,” Rudie said. “But what motivated it, I’m at a loss to say.”
Aftermath of Diane’s death
Diane’s murder took a devastating toll on her loved ones.
Hierlmeier, her fiancé, returned to basic training heartbroken, with questions that would never be answered. A little more than a year later, on Feb. 16, 1968, the private first class was killed by a mortar round in Quang Tin Province in South Vietnam.
The murder and lack of charges weighed heavily on the Olkwitzes. The once-happy family began to crack under the strain.
“Beforehand, it was a lot of family get-togethers and a lot of family fun, you know, Sunday meals with relatives,” Debi said. “And afterwards? Sad, just sad.
“We tried to keep it all together, but it was just never the same.”
Zimmer lived in constant fear, thinking that whoever killed her best friend must also know who she was and could come after her as well.
“It took me five years before I would go out at night in the dark,” she said.
Diane’s parents both died young, the stress of their daughter’s murder contributing to their health issues, her sisters said.
Her mother, Irene, who was diagnosed with diabetes shortly before the murder, died in 1973 of congestive heart failure at age 50.
“It was very hard on my mom,” Patti said. “She just kind of gave up is what she did.”
Diane’s father, Robert, followed three years later, dying of a heart attack at 55.
“He didn’t like to show his emotion,” Patti said, “but we would catch him once in a while crying.”
Eldest sister Nancy died at 58. And Diane’s brother Dennis, who never gave up his quest to solve his sister’s murder, suffered a debilitating stroke at 50 and died 12 years later.
Today, all that remains of the family is Patti, Debi and their brother Edward. They still hold out hope there will be some kind of closure.
“I’d like somebody to come forward,” Patti said. “Or even if the person’s dead, that they told somebody before. Just so that we know.”
But even if the case is never solved, the sisters have refused to let Diane’s murder cast a shadow over their own lives.
“Debi and I are extremely strong from this,” Patti said. “God’s kind of walked along our path with us. I really do believe that. He’s helped us both be very strong. And we are not going to give in or give up on ourselves and let this take us.”
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