In a surprise twist to a baffling Southern murder mystery, the main suspect in the June 2019 murder of former Arkansas state Sen. Linda Collins-Smith, will spend 54 years in prison after pleading guilty to the murder in court this morning.

“I went to Linda’s house, and I intentionally killed her and then hid the body,” Rebecca Lynn O’Donnell, 49, told the judge, according to ABC News affiliate KATV in Little Rock.

The bombshell plea change follows one year after prosecutors in the case announced their intention to seek the death penalty against O’Donnell, who worked as both an aide to the senator, and later an employee of Collins-Smith’s business. The two were considered close friends.

Still, many questions remain — most prominently: why? Details remain sketchy.

After previously pleading not guilty to capital murder, O’Donnell changed her plea to guilty of first-degree murder and abuse of a corpse during a hearing in Pocahontas, Arkansas.

O’Donnell also pleaded “no contest” to two counts of solicitation to commit capital murder in another county. Those charges stem from what prosecutors have described as a murder-for-hire plot while she was in custody. Those pleas will be treated as guilty pleas.

O’Donnell will serve 40 years for the murder, 14 years for the solicitation counts and three years for the abuse of a corpse charge.

The twists and turns in the case have confounded the small community in Pocohantas, about 145 miles northeast of Little Rock.

Numerous judges and a prosecutor have stepped down or recused themselves from the case in the 13 months since the June 2019 murder — which left the ex-senator’s body so damaged that she initially couldn’t be identified by authorities, even though she was discovered outside her home.

“The condition of the body prevented any immediate positive identification,” Randolph County Sheriff Kevin Bell said during a June 6 news conference.

“I was the one that found my mother’s body on June 4th 2019 at her home,” Collins-Smith’s son, Butch Smith, said in a statement on Thursday. “She was lying face down wrapped in one of my old comforters and shoved under a tarp in her driveway. I will never not be able to see that picture burned into my brain.”

Smith said in the statement that he believes O’Donnell was stealing money from his mother and when she confronted O’Donnell, she was stabbed to death.

The initial judge overseeing the case sealed the records of the investigation before recusing himself, leaving many in the small Arkansas community wondering what could have prompted such a heinous homicide. All prosecutors have revealed to date is that the motive for the murder appeared to be financial in nature.

O’Donnell was arrested a week and a half after the murder while driving to Collins-Smith’s memorial service. She was the last person to see Collins-Smith alive, her fiancé Tim Loggains told ABC News in a June 2019 interview, and the two women were so close that O’Donnell acted as a witness in Collins-Smith’s divorce.

“I just told her, they found Linda dead,” Loggains said in that interview. “She collapsed.”

Loggains said she was the last person known to have seen Collins-Smith alive on May 28 when the woman took her to lunch. He described their relationship as being like sisters.

“She’s not capable of this,” Loggains told ABC News last year. “Either she is the best actress in the world and completely fooled me or there’s not a chance she did this.”

Late Thursday, Loggains released a statement in which he described Collins-Smith as a “beautiful soul and a dear friend to me.”

“Initially, for various reasons, I believed with all my heart that Becky was innocent,” he said in the statement. “No one wants to believe anyone close to them is capable of doing something so heinous. My heart at that time would not let me believe what I later learned to be true – that Becky murdered Linda. That realization was one of the most difficult of my life. To accept that I lived with someone so deviant, someone who could not only take a life but the life of someone who helped her in so many ways, without any indication of the darkness in her heart, was heartbreaking.”

Still, pressing questions about the case could soon be answered.

“Everything that is not under seal will be available online,” Judge John Fogleman told the court after O’Donnell changed her plea. “It will be a few days before it can get scanned and she can check to make redactions. Be patient with the court and clerk, it will be available online one week from today”

The judge then instructed everyone but the family to leave the courtroom.

Defense attorney Lee Short told reporters, “This is good for the Collins’ family, they’ll be able to move on.”

Collins-Smith’s family released a statement after the proceedings.

“Today our family has found swift justice by way of a plea deal,” the statement reads in part. “We know that there will be some that will not be satisfied with that outcome today. And we realize that whatever punishment [O’Donnell] receives it will never be enough …. It will never bring my Grandpa’s daughter back or my Mother back or our children’s grandmother back. No amount of punishment will ever fill that void that [O’Donnell] made in our lives the day she killed our Mother.”

“Today we find some shred of peace that Rebecca O’Donnell will be put away in prison for a very long time unable to hurt anyone else. If my Mother was here today I have no doubt that she would quote the Bible and tell us that we can find peace in God.”

ABC News’ Josh Margolin and Rachel Katz contributed to this report.