A KSFY investigation into one of this region's most tragic cold cases.
More than 35 years ago, a body was found abandoned in a farm ditch near Rock Rapids, Iowa.
It was the body of a woman who had been violently murdered.
For decades, finding those who killed her to justice has been a series of dead ends.
But investigators now know more than ever. Tonight, they're sharing with KSFY what they have learned about who killed Wilma Nissen.
In October of 1978, "Laverne & Shirley" was the top show on television.
And on the radio, Exile was burning up the airwaves with their song "Kiss You All Over"..
And on October 4th of 1978, a body was found along this quiet dirt road just west of Rock Rapids, Iowa.
The body was badly decomposed; naked from the waist up, her feet tied together....her bottom jaw missing.
Her name was Wilma Nissen and her life ended violently.
Investigators recovered the green khaki pants she was wearing and a silver and gold friendship ring.
For years, it was all investigators had to go on.
They weren't even able to identify who she was until 2006.
"Frustrating. Very frustrating. You want to have closure." Jerry Birkey is Chief Deputy with the Lyon County, Iowa Sheriff's Department.
He has been investigating the murder of Wilma Nissen for 14 years and tells me, Nissen was murdered so violently and in such a specific way that he can not reveal how she was killed...because it is only something the killer would know.
But he does say, this case is the definition of a cold case. "Very cold. I don't think we received a tip in 2013 at all. Now we did receive a tip in 2014 that we are currently working on."
Birkey won't tell me what the tip is, but he is ready to reveal some information that has previously been unknown.
The Lyon County Sheriff's Department has the name of a person they believe was present the night Wilma Nissen was murdered. That person has been brought in for questioning and asked specific questions about Wilma Nissen's murder. "We have a person that has failed a polygraph on two different occasions."
Birkey also says, his department has recovered DNA from the rope used to tie Wilma Nissen's feet together and that the DNA has been analyzed and that is does not match their identified suspect. I asked Birkey what that means. "That there was more than one person there." In fact, Birkey believes as many as three people were there the night Wilma Nissen was murdered and her body dumped in this ditch.
"Its been a mystery....all the time." Roger Oliver has lived in Rock Rapids since 1967 and serves as a board member for Riverview Cemetery, where for years Wilma Nissen was buried under a generic marker, since replaced with a proper gravestone. Oliver was there when Nissen was properly buried in 2006. For more than 35 years, Oliver has kept tabs on every development in the search for her killer. He's hopeful there will be justice for Wilma. "Whether they'll ever solve it, I don't know. but they're still working on it."
On the walls of Chief Deputy Jerry Birkey's office are drawn out two timelines. What Wilma Nissen was doing in the months, weeks and days before her death....and what their identified person of interest was doing in the months, weeks and days before Nissen was murdered.
Birkey says the identified person...who has failed two polygraphs....is known to law enforcement in both Yankton and Sioux Falls.
In addition, Birkey says he is looking for a second person of interest....whom he revealed to me during our interview. "Probably our biggest missing link right now is we are looking for a light skinned black female who was a prostitute/dancer in the Sioux Falls area and went by the name of Peaches. And we know she was from Canada. If we could locate her, it would be a big help."
Many parts of this investigation are uncomfortable to talk about.
Including this part: some in Rock Rapids are actively encouraging the Lyon County Sheriff's Department to stop looking into this case; saying too much time has passed, too much money has been spent and that Wilma Nissen wasn't a local girl; she was a transient from California with a history of theft and prostitution arrests.
Jerry Birkey says none of those things matter: he says what truly matters is that a killer is brought to justice.