The Unsolved 5-Decade Cold Case of Teen Secretary Stabbed 100 Times

The family of a 19-year-old secretary clings on to hope that, after 53 years, new clues might emerge that will solve the murder in which she was stabbed over 100 times at the Wisconsin factory where she worked.

Best friend alerts authorities something is wrong

In 1966, 19-year-old Diane Olkwitz worked as a secretary at a factory in Menomonee Falls Wisconsin. She began working there after graduating from Menomonee Falls high school 18 months prior.

The factory employed 25 workers and their shifts ended each day at 3:30 PM. Diane remained for an additional hour, working alone in the factory until 4:30 PM every afternoon in order to accept late deliveries and answer calls.

After her shift, Diane would drive to another nearby workplace to pick up her best friend, Diane Zimmer, and the 2 Would Dr. home together.

But on November 3, 1966, Zimmer waited and waited but Olkwitz never showed up. Zimmer caught a ride from her employer’s wife who drove her over to Kenworth Manufacturing Co. to see why Olkwitz wasn’t answering calls and hadn’t shown up.

The pair spotted Olkwitz’s car in the parking lot.

They walked up to the plant and peered through the window, and spotted Diane’s purse on a desk, as well as her coat hanging near the closet, but no sign of Olkwitz. They tried all the doors around the factory but all were locked.

Unsure of what to do next, the pair walked to another factory next door where Diane’s brother Dennis worked. All three then walked back to the Kenworth factory and a supervisor had just arrived and was getting ready to do some after-hours work.

It was now 5:20 PM. The supervisor unlocked the shipping room door and the four made a gruesome discovery.

Teen Secretary stabbed over 100 Times

Upon entering the factory, about 20 feet away from the door, the group of four people spotted Diane Olkwitz lying face down in a pool of her own blood. They summoned law enforcement authorities.

After the initial investigation,  the Waukesha County coroner James Welch determined that Diane had been stabbed 106 times with a knife that most likely had a 3-1/2 inch blade with one cutting edge.

She had at least 30 stab wounds to the chest, neck, and head, as well as 35 stab wounds in rows down the sides of her back. She also had defensive wounds on her arms and the back of her hands. Her nose had been broken.

The wounds measured from 1/2 to 3/4 of an inch in width and from 2-1/4 to 3-3/4 inches in depth.

Although Diane was discovered with her knit dress pulled up between her legs and partly off her shoulders, her undergarments had been undisturbed. The coroner determined that she had not been sexually assaulted.

First murder in Menomonee Falls

A murder had never occurred in the otherwise quiet village of Menomonee Falls, which is just outside Milwaukee’s northwestern city limits.

In those days, big-city crime never made its way in from Milwaukee and children routinely played unsupervised after dark. People hardly locked their doors.

Theories about the crime

One of the leading theories about the crime was that the killer may have been someone familiar with the plant’s layout, as well as aware that Diane would be alone at that hour.

This supported the theory that the killer may have surprised Diane as she was leaving for the day. Further, they believe that Diane knew her killer.

Police worked the case hard, then it went cold

As the unprecedented crime created deep fear within the community, police worked furiously and trying to catch Diane’s killer. On the very day of the murder, authorities started immediately interviewing dozens of Diane’s friends and acquaintances.

Detectives staked out the scene of the crime in case the killer decided to return. But nothing happened.

Seven detectives were assigned to the case working 12-to-16 hour shifts with no days off in an effort to solve the crime.

Authorities also shipped off more than 100 pieces of evidence to the FBI in Washington, D.C. for expert analysis, including Diane’s clothing and fingerprints lifted at the scene.

Over the weeks and months that followed, investigators interviewed more than 500 people. They narrowed this list down to what they believed were six strong suspects. However, all had alibis.

One suspect stood out

Diane’s close friends and her family felt strongly about one person in particular – the son of her employer, whose unwanted advances had left Diane feeling frightened.

Diane’s sister, Patty said, “He obviously was attracted to her [Diane] and had been bugging her to go out with him…And she just didn’t want anything to do with him.”

Police extensively questioned the employer’s son. He stated he was with family members at the time of the killing, all of whom backed him up, providing him with an alibi.

Modern DNA testing comes up empty, strongest suspect can’t be tested

In the 1990s, police used improvements in DNA technology at the time to search for a new match. However, they came up empty.

Police wanted to test the DNA of one of their prime suspects – the employer’s son – but it wasn’t possible. The employer’s son died in 1991. Further, his body had been cremated in the whereabouts of his remains were unknown.

However, the police were able to obtain a court order to exhume the bodies of the employer’s son’s parents to obtain DNA samples. There was no match.

With no new leads or other prime suspects to obtain DNA from, the case went cold again and back to square one.

Police seek information in the case

Authorities have not given up trying to solve this 53-year-old cold case murder.

Police are urging anyone who might have information that they believe may help solve the murder of Diane Olkwitz to contact Lt. Steve Rudie of the Menomonee Falls Police Department at (262) 532-8705.

Anyone can also submit a tip anonymously, by contacting Crime Stoppers of Waukesha County at (888) 441-5505 or online at