OSAGE COUNTY, Okla. (KFOR) — 47-year-old wounds are now being reopened as the Osage County Sheriff’s Office has been following a trail of evidence in a cold case that leads them to believe the infamous BTK killer was involved.

Rewinding back to 1976, Mike McCartney told NewsNation affiliate KFOR the usual summer plans consisted of going to the lake and “just have a good time.”

McCartney was only 16 years old at the time. He’s now 63.

“It was just another summer,” said McCartney.

Quickly into the summer, a shadow of fear cast over the City of Pawhuska.

“People were, of course, upset. They were scared. Just not understanding exactly what happened,” recalled McCartney.

Then 16-year-old Cynthia Dawn Kinney vanished into thin air and without a trace.

KFOR visited the Osage Laundry in Pawhuska where Kinney was reportedly last seen.

“Cynthia Kinney was working, filling in actually for a friend of the family who owned the laundromat,” said Osage County Undersheriff Gary Upton. “She actually specified that she needed to be out of the laundromat by the time that she had to be at cheerleading that day.”

Undersheriff Upton stated based on the scene in 1976, Kinney didn’t appear to have been forcibly removed from the laundry mat.

“There was no sign of her after her disappearance, with the exception of some change on the table and a half-eaten doughnut that was there,” said Undersheriff Upton.

Undersheriff Upton said tips flooded the Sheriff’s Office shortly after Kinney’s disappearance, but none led officials to a credible suspect.

The Osage County Sheriff’s Office has started exploring a different suspect in the last year who they now believe could have killed Kinney.

“We had a homicide occur last fall, and it was a pretty big investigation with, you know, four people arrested or five people at the time, several more. Pretty complicated case. I woke up 1:30 something in the morning, tossed around, couldn’t get back to sleep. I thought, I’m just going to get up, so I go and make a pot of coffee, flip on the TV,” said Osage County Sheriff Eddie Virden. “There’s a documentary on about the BTK killer. I’m sitting there, drinking coffee, waiting for daylight. As I’m watching it, things start kind of popping out that are familiar.”

Bits and pieces of the documentary made Sheriff Virden reflect on Kinney’s case and wonder if she could have been a victim of BTK’s. A major piece of the puzzle that stuck out to Sheriff Virden was the time in which BTK would kill/kidnap his victims.

Sheriff Virden said BTK would act mid-morning, which is around the same time Kinney disappeared from the laundry mat.

“Fearing that type of stuff, you’ve got to make a decision. We decided to take two investigators and try to talk to him, do what we call a background, you know, not questioning about any crimes specifically, just seeing if he has any ties there,” explained Sheriff Virden.

Sheriff Virden traveled to the El Dorado Correctional Facility in El Dorado, Kansas. BTK killer, Dennis Rader is currently serving 10 life terms for 10 horrific murders.

“When Dennis came in, the first thing he says is, ‘I only killed the 10 people that I’m in here for. So I didn’t do whatever you think I did,'” recalled Sheriff Virden.

He told KFOR he asked BTK to run through the events in his life.

Sheriff Virden said he questioned BTK for roughly four hours and there was seemingly no connection.

As the questioning was wrapping up, Sheriff Virden said BTK asked him if he wanted to know one of his favorite fantasies.

“I said, ‘Sure, why not?’ And he said, ‘I always wanted to kidnap a girl from a laundromat,'” said Sheriff Virden. “We hadn’t mentioned anything about that and he throws that straight up like that. Of course, I tried not to show any emotion.”

BTK was writing a book/journal about his life’s work.

One of the chapters was filled with what BTK called “projects.”

A journal entry alludes to a significant event marked as “PJ-Bad Wash Day” during a period in which BTK acknowledged being outside the Wichita area, according to the Osage County Sheriff’s Office. “PJ” is BTK’s abbreviation of the word “Project.”

“C-9” makes reference to Chapter 9 in BTK’s unpublished manuscript that was intended to give details on all the murders he actually committed, per the Osage County Sheriff’s Office.

In the journal entry, BTK describes watching a nearby laundry mat for a target he describes as “the brunette.”

BTK wrote the laundry mat was a “good place to watch victims and dream.”

“I can imagine him coming in and asking for [Kinney’s] assistance in getting some baskets of laundry out of the trunk of his car and her being very helpful and and coming out there. And as soon as he opened the trunk, probably either putting her in the trunk or maybe making her get in the back seat at gunpoint. He was known to carry a firearm as well,” stated Undersheriff Upton.

When inside the laundry mat, there are three ways to enter and exit the building. Law enforcement speculates the right side door of the business is where Kinney walked out of before BTK kidnapped her.

From there, officials believe BTK drove out of Pawhuska, crossing over the Kansas state line.

The City of Pawhuska is currently home to less than 3,000 people, so Kinney’s disappearance begs the question of how this small city could have been on BTK’s radar.

A bank sits right across the street from the Osage Laundry where BTK could have been installing security.

Undersheriff Upton said the bank was under construction when Kinney disappeared.

“Dennis Rader worked for ADT. ADT, in the national market, had about 80% of the commercial alarms nationwide. And so we suspect that Dennis Rader, being a regional ADT alarm installer, could very well have been in the area and installing the alarm and casing the Osage laundromat,” stated Undersheriff Upton. “He could have been here for a number of weeks.”

As investigators continued digging into Kinney’s cold case, Sheriff Virden said BTK led them back to a property he used to own in Park City, Kansas.

BTK allegedly told Sheriff Virden there was evidence buried in the soil investigators never found.

Panty hose was found underground. However, BTK told investigators there would also be victim’s drivers licenses, but Sheriff Virden said they didn’t find any.

“We hope that items like that could be tested for these victims’ DNA,” said Sheriff Virden.

In addition to ripping through a piece of BTK’s former property, Sheriff Virden has spent hours reviewing drawings and photos from BTK.

The Osage County Sheriff’s Office has provided KFOR with some of the evidence reviewed by investigators. KFOR has elected to not show everything received as some images are too graphic.

Undersheriff Upton told KFOR the drawings are of victims bound and gagged. He added the drawings were sketched from BTK’s memory.

The girl in the green dress depicted above has possibly been identified, according to Undersheriff Upton.

Law enforcement speculates the pencil drawing could be Kinney.

Drawings of barns and silos from BTK have also been reviewed.

The above drawings are allegedly ideas of BTK’s for torture chambers.

To the side of the one drawing, BTK lists what he wanted to include in the silo such as an elevator, wet bar, shower, sink, sand box, pole, pool and high chair.

The above photo shows a Kansas barn and silo that has since been torn down.

Sheriff Virden said their investigation led them there, but they were unable to locate any evidence on/underneath the land.

According to Undersheriff Upton, that Kansas silo and barn were near a Boy Scouts campground where BTK would often travel to. BTK was a Boy Scouts leader.

Sheriff Virden told KFOR he has also found a loose button that appears to have been ripped from a woman’s blouse. He said he found it in a barn, but didn’t disclose where the barn was.

The blouse button could belong to Kinney, according to Sheriff Virden. He said he is still trying to figure it out.

KFOR asked Sheriff Virden why after nearly 50 years worth of a mystery he continues to investigate.

“If you have any children, you know, if you have a sister or I don’t really care who it is, if you have somebody in your family that vanished without a trace, you need answers and closure. Additionally, if you’re a victim, you need justice,” explained Sheriff Virden.

While the investigation continues, McCartney tries to remember the girl he once knew.

“Cindi was fairly new to Pawhuska, but she had a lot of great friends. She had made a lot of friends. If I remember correctly, she was going to be on the cheerleading squad,” said McCartney. “She was always a happy girl. She was sweet. She was good friends with some good girls I know. She was just a super sweet girl. She’s the girl that was going to be your best friend.”

McCartney said his high school graduation class was close knit.

“You always have to think about what if and where would you be right now? You can sit and think about a lot of things. It’s tough for me to not think of her family and what they might be thinking if she had kids,” said McCartney.

He said the toughest part is to see Kinney’s family go through yet another open investigation into their daughter’s case.

“It’s kind of like a loved one that has gone on,” he added. “You just wonder if you could have helped them.”

McCartney hopes this investigation provides Kinney’s family with answers.

KFOR asked McCartney if there was anything he wishes he could tell Kinney if she was listening.

As he fought back tears, he said, “We think of her. She just has not ever been forgotten, that’s for sure. And we think of her often and we think of her family often.”

McCartney told KFOR off camera he could feel Kinney’s presence in the room when the question was asked.

McCartney said there’s so much more he wishes he could say to Kinney, but what he wants her to know is her memory continues to live on in Pawhuska.

The Osage County Sheriff’s Office has created a National BTK Task Force to help aid in Kinney’s cold case.

In addition to Kinney, Sheriff Virden believes there are several more victims and he’s hopeful they’re getting closer to solving those cases as well.