The residents of Casper, Wyoming are desperate to find one of their own. Jason Mattera has the troubling missing-persons case of Kris Richardson.

This millionaire mogul's disappearance is the talk of the town. And many are asking, Was she the victim of a random attack, or was it revenge for something else?

Kris Richardson, a very rich widow, suddenly goes missing, disappearing into the thin air of Casper, Wyoming. Cops wonder, Did her own children kidnap her for the money?

Did Kris have a lover, or a secret admirer? And what does this trucker know?

It's the question haunting the tiny town of Casper, what happened to Kris Richardson?

Kris, a beloved mother and grandmother, was last seen alive on a chilly October evening in 2014 at about 5:30 p.m.

"She was seen at the mailbox getting her mail, and then a next-door neighbor of hers saw her car pull into the garage," said Amber Fazio, Kris's daughter. That was her daughter Amber's birthday, and she tells Crime Watch Daily her mom just stopped by to drop off a card, and give her a hug.

"That night she came by to bring me a birthday card and just tell me to have a great night and then she left and went home," said Amber. "It was the normal routine. She gave my kids a kiss and said 'I'll talk to you guys tomorrow.'"

Next morning, Kris Richardson is a no-show at work. Amber and her husband, Pete, race to Kris's home just around the corner.

"When I saw her car still sitting in the garage I knew that something was not right," said Amber. Inside the house, sheer panic sets in as Amber and Pete search room to room. "Everything, a purse sitting on the kitchen counter with $700-plus in it: driver's license, cellphone, passport, birth certificate, suitcases, clothes."

Casper Police Detective John Hatcher is on the receiving end of the panicked 911 call. At the house, crime scene detectives hope to discover clues that will answer the question: Where is Kris Richardson?

"Inside there are no signs of a struggle, there was no signs of anything of any foul play or anything had happened," said Det. Hatcher.

Then Detective Hatcher spots it.

"Her cellphone was laying on the bed," said Hatcher. "Again she was a owner-operator of a trucking company. That's a pretty large trucking company. Here in Casper, Wyoming. And all the trucks have to be dispatched through her, that cellphone is the way she got it to a person that's running a company. And that's the only way you can make money is to have that cellphone. That was very suspicious," said Hatcher.

Detectives focus their investigation on the Richardson children. Financially, family members would have everything to gain with Kris out of the picture.

The investigation heats up when detectives run a financial background check on Pete and Amber. Could there be a paper trail linking the multimillion-dollar trucking business and Kris's disappearance?

After multiple interviews and even lie-detector tests, Kris Richardson's family members remain persons of interest.

As detectives comb through the trucking company's financial record books, that's when they make an explosive discovery, between the bills and invoices: love letters. And they're addressed to Kris.

The entire focus of the investigation is about to shift to a man police say had an obsession with Kris Richardson. The letters are from a man named Bud Boyles. But who is he? And did he have anything to do with the disappearance of Kris Richardson?

"Bud Boyles was a truck driver for Richardson Trucking, had worked for them for a while," said Det. Hatcher. "Over the years he got a friendship with a lot of the drivers, with Kristi Richardson again but his kind of went a little more than the other drivers. He wanted to pursue something a little more romantic relationship with her."

Come to find out, Kris's children tell our Jason Matera they knew about the letters.

"She mentioned it to us a couple of times about, he had written her a letter or called her one day, but never did she say 'I need someone to take care of this,' or 'I need to call the police,'" said Kris's daughter, Amber Fazio.

Kris never contacted authorities. Instead she told her husband.

"My dad confronted him one day at Richardson Trucking and said, 'You're crazy, I don't know what your deal is, she's not interested, and knock it off,'" said Amber.

Kris's children thought it ended then and there. But it didn't.

"He continued to call her and tell her that he didn't understand, he loved her, and why was she not loving him back," said Amber.

When Kris's husband passes away, her children say Bud Boyles didn't miss a beat. In less than 48 hours, he was back at it.

At this point, Kris begins to save the letters in Bud's employee file. Kris's kids claim this a tangible paper trail.

In a Crime Watch Daily exclusive, the elusive letters buried in Bud Boyles' employee file are finally exposed.

Detectives find no evidence Kris ever reciprocated or had any romantic interest in Bud Boyles.

In fact, according to her children, in days leading up to her disappearance, she became increasingly afraid of him.

"At a certain point in time she got uncomfortable with him being in the office without another person around and so she always made sure if she knew he was going to be there if he was coming that someone else was there as well," said Kris's daughter Tracy Richardson.

And Kris may have had good reason to be terrified. Even though Bud Boyles has never been charged in the disappearance of Kris Richardson, detectives agree the letters seem to express an extreme infatuation and escalating anger.

Then just like that, according to Amber, Bud Boyles quits working for Richardson Trucking.

Days later, Kris vanishes. A coincidence?

Detectives question Boyles. He has an alibi for the day Kris went missing -- all except for three crucial hours.

Is Bud Boyles hiding something? Crime Watch Daily wanted to find out from the man himself. But there was no answer at the door when Crime Watch Daily visited his home, and he did not answer his cellphone.

Crime Watch Daily tracks down Bud Boyles for an exclusive, first-ever on camera interview, about the mysterious disappearance of a wealthy business woman who cops say was his secret obsession and the object of his desires.

Crime Watch Daily affiliate KTWO's Mark Hyman found Bud Boyles at his workplace in Casper, Wyoming.

"Everybody seems to know more about it than I do. I hear this stuff coming down the pike and wonder where it originates," said Boyles.

"I worked for her for 10 years, we got along pretty good," said Boyles. "When Ronnie passed away, I left because I was the only owner-operator and I knew I didn't have a future there because he was the reason I stayed for those 10 years,and that's all I have to say."

A $250,000 reward was put up by Kris's children for any information that will help find their mother.

If you have any information related to the disappearance of Kristi Richardson, you are urged to contact the Casper Police Department at (307) 235-8278.