On the night of October 29, 2011, the small town of Dyersburg, Tennessee was abuzz with Halloween excitement. That spirit really darkened after Karen Swift, a 44-year-old mother of four, disappeared. All that remained were her car, found abandoned by two hunters on a country road the next morning, and the two broken cell phones discovered near a neighbor’s house.

Six weeks later, what started as a missing persons case became a murder mystery as Karen’s body was found hidden under a tangle of vines by a caretaker near Bledsoe Cemetery in Dyer County. An autopsy determined he had suffered head trauma.

The case went cold with no arrests made for over a decade, casting a shadow over Dyersburg Halloween and haunting the community. On August 8, 2022, the cold case was unfrozen when police announced the arrest of Karen’s husband, David Swift. After being indicted by a grand jury, David was charged with first degree premeditated murder. He pleaded not guilty to the charge.

Watch the “20/20” episode “Her Last Halloween” airing Friday, Nov. 1 at 9 p.m. on ABC and streaming on Hulu beginning Nov. 2.

The arrest came as a shock to many, including David and Karen’s 20-year-old daughter Ashley.

“I remember, you know, trying to figure out why,” Ashley Swift said in a new interview with “20/20.” “Why just now? Why after so many years is this happening?”

David’s trial began on May 28, 2024. Community members wondered what evidence would explain his sudden arrest after 11 quiet years.

On the first day of the trial, the prosecution warned the jury that they would not be presenting this case as a DNA case, nor would their key evidence involve fingerprint or ballistics tests.

Instead, prosecutor Danny Goodman painted a picture of a rocky marriage, as Karen filed for divorce three weeks before her disappearance. The two have separated in the past, divorcing as recently as 2000 before remarrying the same year, but the indictment suggested it was more permanent this time.

On the morning of October 29, 2011, the night before Karen disappeared, she rejected David’s conciliatory offer to have dinner with him later that evening. The state theory was that rejection means “eat(Eng)” at David, as Assistant District Attorney Tim Boxx said during the trial, and Boxx speculated that David was beginning to understand that Karen was truly leaving him, “and this time, it’s forever.”

Daniel Taylor, David’s defense attorney, argued that David’s attempts to reconcile with Karen should not be read as indications that he feels rejected, but rather as evidence of his hope for a revitalized relationship.

“David thought maybe they could work it out again like they did the first time?” Taylor asked during David’s trial. “Was he hopeful about it? Yes.”

The prosecution also alleged that David sought to control and supervise his wife’s movements during the final days of their marriage.

In response, the defense worked to convince the jury that David’s alleged actions did not exist in a vacuum.

Karen’s friends and family have claimed that Karen took on something of a new identity in the period leading up to her murder. She became involved with a new circle of friends who often attended parties at The Farms Golf Club in Dyersburg. He was also said to have started drinking and going out more.

“Karen’s behavior changed with this new group,” David’s friend Kim Greene told “20/20” in an exclusive interview. “She was determined to be out there having fun with them instead of staying at home with the kids where she belonged… (Davide) he was just going out to see where his wife was.”

Taylor also questioned the accusation’s premise that David had “control” over his wife. Taylor pointed out that he had access to their joint bank account and that Karen was able to go wherever she wanted. He also pointed out that David frequently checked on Karen, “and got on her nerves”, but no violence was involved.

David echoed that sentiment in his interview with “20/20.”

“I have never raised my hands on anybody, now or ever,” David told ABC News’ Juju Chang. “And I certainly wouldn’t do that to my wife or the mother of my children… It’s just not in my character.”

Ultimately, David’s trial ended on June 6 with a verdict of not guilty on the charges of first-degree premeditated murder and the lesser included charge of second-degree murder. The jury, however, was unable to reach a verdict on the charge of voluntary manslaughter — a deadlock that led to a mistrial on that charge.

The jury was deadlocked on hearing the stalking charges David faces in Jefferson County, Alabama, related to his ex-wife, Kelly Essman. He met Essman on the Christian Mingle dating site in 2014, three years after Karen’s death, and the two married in May 2016.

Essman, who has not publicly shared her story before, spoke to “20/20” in an exclusive interview.

“I look at how lightly I spoke (Davide)and he believed everything he told me,” Essman said. “And the feeling I got was that he was sincere. Why didn’t I see it? How do I trust that I can see through anything else?”

“20/20” obtained footage of what appears to be David at Essman’s residence in the middle of the night after they were already separated.

“I shot up,” Essman told “20/20.” “And there he was in my backyard in the middle of the night… He had to drive 40 minutes, one way, to get to my house.”

David was charged with criminal prosecution in Alabama in July 2023 and has yet to enter a plea. His attorney did not respond to a 20/20 request for comment on the case.

Despite the allegations against him, David’s friends and family said they saw a gentle person.

“David is such a kind person,” Kim Greene said of her friend. “He wouldn’t hurt anybody.”

Ashley Swift also recalled her father’s compassionate moments, talking to “20/20” about a time she saw him helping a mom pay for her groceries during the holidays.

“He was putting things back while checking,” Ashley recalled. “And my dad ended up covering everything so her kids could have a good Christmas. Things like that really stand out to me.”

On October 15, the Tennessee Court of Appeals denied a motion by David’s defense team to dismiss the case involving Karen’s murder, setting the stage for a new trial on the charge of voluntary manslaughter. He pleaded not guilty to the charge.

When Karen Swift first disappeared in 2011, the Dyersburg community was gripped by a deep hunger for answers — answers that could provide closure for them and justice for Karen.

After 13 years and one attempt, this wish remains unfulfilled. But Karen’s memory — and the hope of those who cherish her — still promises to endure.

“I finally know the truth about my family,” her daughter Ashley told “20/20.” “And I know my mother would want me to keep fighting for her.”