Woman found guilty in spouse's murder speaks out for first time since her conviction

Fifteen years ago, Miriam Helmick was sentenced to life without parole for the murder of her second husband, Colorado businessman Alan Helmick. She currently sits behind bars at the Colorado Womens Correctional Facility serving a prison sentence for a crime she says she did not commit.

Now, Miriam Helmick is speaking publicly for the first time since her conviction, offering details about her relationship with Alan and the events of the fateful day when he died.

It won't be over for anybody until it's over for me, and I do have hopes, Helmick said. I know that I didn't kill him.

Helmick spoke with ABC News' John Quiñones in a prison interview for a new 20/20 airing Friday, January 31, at 9 p.m. ET on ABC, and streaming the next day on Hulu.

The couple's story began on the dance floor. Miriam, a dance instructor, taught Alan ballroom dancing and their friendship blossomed into romance. Their nuptials were a second marriage for them both, and they had dreams of sharing a life together. Miriam describes Alan as a very kind, very sweet man. She said he was funny and well liked in the community.

He always had your best interest at heart usually, Miriam Helmick said about Alan.

Their dreams came to a sudden and tragic end on June 10, 2008. Miriam said she was running errands that morning and planned to meet Alan for lunch. When she couldnt reach him by phone, she told police she returned to their Whitewater, Colorado, home and found her husband lying in a pool of blood.

The house appeared ransacked, and Miriam frantically called 911.

Robin Martin, an investigator with the Mesa County Sheriffs Office who worked on the case, remembered how the first officers who arrived on the scene said they found Miriam distraught and kneeling over her husband.

Alan was on the floor in the kitchen, Martin said. It looked like he had been shot in the head. We had a bullet casing next to his body.

Police found no one else in the house. As they conducted a sweep of the home, they noticed drawers pulled out in the kitchen and a trash can tipped over in Alans office.

Investigators followed routine protocol to thoroughly review the spouses whereabouts. They tested Miriam for gunshot residue and swabbed her clothes for blood. Those tests came back negative. She even showed police all the printed receipts from where she was shopping that day.

"She actually went from one end of the valley to the other end, Mesa County Prosecutor Rich Tuttle said. We were able to track her movements not only by her receipts, but by her cellphone interacting with cellphone towers.

Miriam also told police about a shocking incident that happened just six weeks earlier.

Miriam said that someone had attempted to blow up Alans car. The couple had been in nearby Delta, Colorado, when Miriam went to the restroom and came back to see Alans car on fire. A wick was found in the gas tank.

He came in saying that his car was on fire, and he asked me to get water, and that's all I know about it from there, Miriam Helmick told 20/20.

When investigators in Delta asked Alan if Miriam could have been the one to start the fire, Alan insisted she would not have done that and asked that police stop the investigation.

Oh God. No, I don't think that, Alan Helmick is heard on a recording of the police interview about the fire incident in Delta, Colorado. Why would she do that?

In her 20/20 interview, Miriam Helmick suggested that Alan might have started the fire himself. She said that he could have been trying to collect insurance money.

The thing about Alan (was) if he had thought I had done it, he'd have helped me pack a bag, put me on I-70, Helmick said. According to Miriam, Alan told her the investigation was done and that was the last they spoke of it.

As days passed with no suspects in custody for Alan's murder, Miriam Helmick said she became convinced she was being watched, reporting that weird things were happening around her house.

Then weeks after Alans death, Miriam said she found a disturbing card on her doorstep with a message inside that said, Allen [sic] was first, your [sic] next. Run, run, run!

It was a mysterious note that made Miriams friends worry for her safety and that she may be the next target.

Miriam calls me and shes frantic, Jeri Yarbrough recalled of the incident with her friend. She goes, What should I do? And I said, Well, you need to hang up the phone and call the police and get out of there. I said, because somebody could be there trying to hurt you.

When Martin investigated the card, she said she was shocked by what she tracked down. The surveillance video from the store where the card was purchased showed it was Miriam Helmick who bought that greeting card.

It was her. She was wearing the same style of shirt that she had walked in with her [police] interview, Martin said.

In her interview with ABC News Correspondent John Quiñones, Helmick claimed that she saw suspicious cars driving around her property in the time after Alans death and that she felt police were not taking it seriously. She said she wrote the card herself in the hopes that police would up their investigation.

"Maybe it was a really bad decision, Miriam said, but at the same time, I thought they would come out and actually look to see who this person was because it didn't seem to be care very much about my safety at that point, and they hadn't told me that I was a person of interest.

Prosecutors said Miriam alone was responsible for Alans death. Six months after the murder, Miriam was charged with first-degree murder, attempted murder for the car fire incident and several counts of forgery. Prosecutors claimed Miriams motive for murder was money.

There were suspicious bank account activity where it appeared that Miriam had forged multiple checks from Alan's account, Tuttle said. All told, she had taken about $40,000 out of his account through writing those checks.

Miriam told Quiñones that Alan knew that she was writing those checks. She said that they owned a dance studio and a horse farm together and Miriam was responsible for payroll and other business expenses.

In December 2009, a jury found Miriam Helmick guilty of first-degree murder in the death of Alan Helmick. She was also convicted of attempted first-degree murder for the car fire and multiple forgery counts. She was sentenced to life in prison plus 78 years.

Tuttle told Quiñones he thinks the jury got it right. I think there's no way that Miriam Helmick should ever be free in society again. So, life in prison without the possibility of parole, it's the only sentence that serves justice, Tuttle said.

From prison, Miriam said she is determined to clear her name and will not stop until she is successful.

I know that I didn't kill him, Helmick said. I don't care about anybody else's opinion. What I want more than anything is to prove that.

Miriam Helmick has filed numerous appeals with the courts. They have all been rejected.

When it comes to Alans family and friends, there are some things that they would rather forget, they told "20/20."

I try not to think about the murder. I more like to think about the fun times that we had with Alan. Those are good memories, Ed Benson said of his friend.

Alans friends prefer to remember him as someone who was a lot of fun.

"He was the kind of guy you could meet and have a drink with and have a good laugh, Alans friend, Bob Cucchetti, said.