2 cold case murders in Menomonee Falls -- both decades old -- now solved

 

MENOMONEE FALLS, Wis. (CBS 58) -- Two murders in Menomonee Falls, both decades old, have been solved.

At a news conference on Wednesday, Oct. 25, city, state, and federal investigators announced that they solved two area cold case murders using new DNA technology.

On Nov. 3, 1966, Diane Olkwitz was found dead in the shop area of what was then Kenworth Manufacturing Company on Silver Spring Drive in Menomonee Falls. Diane was 19 years old at the time. Menomonee Falls Police Chief Mark Waters described it as a grisly murder.

"Diane was lying face down and stabbed approximately over one-hundred times," he said.

Over the years, a number of suspects were vetted and ruled out. And while the case went cold, it was never forgotten.

"We've always had a detective assigned to this case," Chief Waters said.

Because of the quality of evidence collected at the scene in 1966, investigators had a DNA profile of the killer all these years. Through collaboration with other departments, it was determined that a similar suspect DNA profile existed for a 1971 unsolved homicide case in the city of Milwaukee.

In Feb. of 2023, using what's called "forensic investigative genetic genealogy," police were able to identify a suspect. Investigators say they collected DNA samples of relatives to make sure they had the right person. Detective Chris Bellows of the Menomonee Falls Police Department says relatives gave those samples to police voluntarily.

"We would ask their cooperation, we'd explain our investigation to them, and we'd ask if they'd be willing to share their DNA information with us," he said.

After exhuming his body and collecting more DNA, police announced Wednesday that the suspect responsible for the murder of Diane Olkwitz in Menomonee Falls and Terri Erdmann in Milwaukee is Clarence Marcus Tappendorf. Both women were stabbed to death, a motive was never determined. Tappendorf died in 2008.

Chief Waters says DNA was not the only evidence that implicates Tappendorf, investigators can place him at the scene of Olkwaitz's murder.

"On Nov. 3, 1966, the date of Diane's death, Clarence Tappendorf made a delivery across the street from Kenworth Manufacturing," Chief Waters said.

After the announcement relatives of Olkwitz indicated they did not want to interview on camera, but they did express a sense of relief. They said over the years there were rumors and wild theories about Diane's murder. Those theories can be put to rest, and now the entire family has some closure.

Attorney General Josh Kaul lauded the cooperation between departments and signaled that the use of this new investigative tool will continue.

"I hope this sends a message that law enforcement will not give up on solving these cases, whether it is days, months, or even decades," he said.