At 68-years old, Helen Mills showed no signs of old age.

“At 68, a clogger! She was part of a team,” described her daughter, Debbie Segar. “Feisty, she was very fit, very caring and very capable.”

Mills put that high energy into running a little herb shop devoted to health.

Crime scene surrounds the Mill's herb shop in Maryville.

“She was always educating herself and help her customers as they came in,” said Segar.

On an August day in 2002, the corner store where she lived out her passion became a crime scene.

“I didn't even know what I was coming to, I had a message on my phone to get to the store,” recalled Segar.

"When I got there, there was crime scene tape. And that's not someone falling ill, or tripping or collapsing.”

Inside, Debbie Segar learned her mother had been strangled.

Daughter Debbie Segar recalls learning the news of her mother's death.

"I screamed her name. I couldn't go to her, couldn't hold her and couldn’t make it better. She was just gone,” said Segar.

“It’s very vivid in my memory for the fact that it was such a major crime,” said Maryville Police Chief Tony Crisp.

It was his first day as chief.

“Such a terrible crime and happened just hours before my watch began," he said.

Detective Lieutenant Carlos Hess was the first on the scene. 

The location boggled police. Mills' store was just a block away from the department’s headquarters.

“I can see it out my window,” said Detective Lt. Carlos Hess.

Hess was first on the scene and has studied the case tediously.

“We went through all the gambits: robbery, we ruled that out, drifters, everything we could think of,” Hess said. “We feel it was someone she knew, she felt comfortable with them.”

Debbie Segar watched as her father struggled with the loss.

Doug & Helen Mills. Courtesy Debbie Segar

“They were just shy of their 50th anniversary,” said Segar.

Doug Mills battled the heartbreak by relentlessly searching for his wife's killer until the day he died.

“I won’t give up. We will pursue and you will get caught. You will not get away with it,” he told WBIR in a 2002 interview.

Mr. Mills did countless interviews, put up billboards and offered a reward.

A newspaper clipping shows Doug Mill's plea for answers.

“Anybody that would listen to him he was out there,” said Segar. “The day he passed way he renewed the award and just like that he was gone.”

Aug. 31 will mark 15 years since the murder of Helen Mills and investigators are not giving up.

“It’s our obligation and it’s the right thing to do,” said Chief Crisp.

“This is the one that if I had one that gnaws at me,” said Detective Hess. “I feel like we should have solved it early. They deserve it, and Mrs. Mills deserves it."

Helen Mills holding her grandchildren. Courtesy Debbie Segar

“The sad part is someone took her life. She wasn't sick, she didn't fall and she didn't get hurt. Someone made a conscience decision to take her life,” said Segar.

She still misses her mother and the moments they could have shared.

“Helen would have been a great-grandmother. She missed that. She didn't get to see me be a grandma,” said Segar.

She makes it through each day with the strength her mother gave her.

“Well, I’m her. But she was in better shape!” laughed Debbie. “She was energetic. Full of life, truly.”

Through the years, the Maryville Police Department has retested evidence and even brought a homicide detective out of retirement to focus on the case.

If you know anything about this crime you can call the Maryville Police Department at 865-273-3831

They are offering a $5,000 reward for information leading to an arrest.