Future of Kaitlyn Conley uncertain after two murder trials and a conviction

Her first trial ended with a hung jury. 

Her second finished with an acquittal on the most serious charge — second-degree murder — and a conviction for the lesser crime of manslaughter.

Then, in January, the legal saga of Kaitlyn Conley took another unexpected turn: A New York appellate court overturned the 2017 conviction in the fatal poisoning of her boss, a killing the prosecutor had described as “cold-hearted and diabolical.” 

The problem, the appeals panel concluded, was that her defense had not done enough to stop prosecutors from introducing key evidence — details from Conley’s cellphone obtained through what the ruling described as an improperly written warrant.

For more on the case, tune in to “Poison Twist” on “Dateline” at 9 ET/8 CT tonight.

Conley was released from prison earlier this year, and Oneida County District Attorney Todd Carville is weighing whether his office should pursue a third trial. He told “Dateline” he is reviewing the case. The Oneida County Sheriff’s Department, which investigated the death, did not respond to requests for comment.

In the meantime, here are three key moments in the case. 

A mysterious illness and death that ‘made no sense’

July 21, 2015

Mary Yoder, a longtime chiropractor who ran a clinic with her husband outside Utica and was known for her love of health and fitness, was hospitalized with increasingly dire symptoms — vomiting, diarrhea and severe abdominal pain. 

Although specialists were brought in to treat her, by that night, doctors had provided no answers as to what was making her ill, Yoder’s relatives have told “Dateline.” They had to revive her several times after her heart stopped, they said. 

Yoder, 60, was pronounced dead the next day.

“I remember at the time saying, ‘I don’t understand this,’” Yoder’s daughter, Tamaryn Yoder, told “Dateline.” “If there had been a car accident or something, that I could understand. But I don’t understand this. What happened for her body to just quit? Because it made no sense.”

An autopsy later revealed that she had died from colchicine toxicity — a drug used to treat gout. That November, the sheriff’s office received an anonymous letter claiming that Yoder’s son, Adam — then in his mid-20s — had admitted poisoning her. 

The letter claimed Adam Yoder had bought the drug online, dosed her vitamins with it and stashed the bottle under the front passenger seat of his Jeep, former Oneida County Sheriff’s detective Robert Nelson previously told “Dateline.” The letter’s author claimed Adam Yoder was fueled by anger and a belief that his mother’s death would benefit him financially, Nelson said.

In an interview with authorities, Adam Yoder denied the allegations. But when investigators searched his car, Nelson said, they found the container in the precise spot where the letter said it would be. 

Adam Yoder said the bottle had been planted, Nelson said, and detectives were skeptical of the letter’s claims. If Adam Yoder killed his mother, Nelson recalled thinking, why would he bring evidence of the murder to the sheriff’s office, where he had been interviewed? When they looked into his whereabouts at the time his mother was poisoned, they discovered that he’d been on Long Island — 300 miles away. 

Eventually, authorities discovered the letter writer’s identity and came to believe that she was responsible for Mary Yoder’s death. That was Kaitlyn Conley, the receptionist at Mary Yoder’s clinic and Adam Yoder’s ex-girlfriend.

Trying to cast suspicion on chiropractor’s family at trials

June 13, 2016

Conley, then 23, was indicted on charges of second-degree murder, forgery, falsifying business records and two counts of larceny. 

When detectives questioned her about the letter, she’d been working full time at the clinic for a couple of years and involved in an on-again off-again relationship with Adam Yoder. Conley acknowledged writing the letter and told the investigators that her ex had confessed to the killing, video of Conley’s interview shows. She told authorities that he had said he regretted doing it.

Conley said she hadn’t come forward sooner because she was afraid of him.

But when authorities obtained a search warrant for Conley’s cellphone, they discovered that it had been used to search “poison” and “colchicine” multiple times, according to the appeals ruling. And the email used in the drug purchase — “mradamyoder1990@gmail.com”— had been logged into on her device, the ruling states. 

Detectives used those revelations to uncover another key piece of evidence — that Conley had bought the prepaid debit card used to purchase the colchicine, the ruling states. 

When Conley’s trial began in April 2017, prosecutor Laurie Lisi pointed out that on the day Mary Yoder fell ill, Conley was the only other person patients saw at the clinic. And Lisi identified a possible motive in the murder: “Kaitlyn Conley wanted Adam Yoder back. And I submit to you, she poisoned Adam Yoder’s mother, her boss, in hopes of bringing Adam Yoder back to her.”

That plan briefly worked, Lisi alleged. They got back together after Mary Yoder’s death, but then they split up again and Conley sent the letter identifying Adam Yoder as the killer, the prosecutor said.

In interviews with detectives, Conley denied killing her boss. And at trial, her lawyer blamed the death on Mary Yoder’s husband, Bill Yoder, whom she ran the clinic with. According to defense attorney Christopher Pelli, Bill Yoder had the motive — he’d developed a romantic relationship with his wife’s sister and, with a recent inheritance, no longer needed his wife, the primary breadwinner in the relationship — and he had opportunity.

Although Conley was the only other employee seen at their office the day Mary Yoder became sick, Pelli said it was Bill Yoder’s practice to get his work done in secret and make sure no patients knew he was there.

In an interview with “Dateline,” Pelli disputed the evidence found on Conley’s phone. 

“The prosecution couldn’t say that, ‘Katie searched this particular term prior to Mary’s death,” he said. “It appeared that it was afterward.”

Bill Yoder was never charged in his wife’s death and he told “Dateline” that he did not poison her. In court, he testified that his relationship with Mary Yoder’s sister began after her death.

In the first trial, the jury failed to reach a unanimous verdict after deliberating for five days and the judge declared a mistrial. During the second trial, which began five months later, Conley’s new defense attorney did not identify Bill Yoder as a possible suspect, but instead focused on his son, Adam. 

In testimony, Adam Yoder denied the allegations and the prosecution suggested that he, too, may have been poisoned in the months before his mother’s death. After Conley gave him supplements to help boost his memory, Adam Yoder testified, he went to the emergency room with symptoms similar to his mother’s.

Conley’s lawyer denied that she had anything to do with his illness and suggested that he’d made himself sick with the colchicine he’d bought to kill his mother.

On the second day of deliberations, the jury acquitted Conley of second-degree murder and convicted her of manslaughter. She was sentenced to 23 years in prison.

A winning appeal — and release from prison

Jan. 31, 2025 

A state appeals court in New York overturned Conley’s manslaughter conviction after she obtained a new lawyer who argued that Pelli failed to properly challenge the warrant that allowed authorities access to Conley’s cellphone.

Attorney Melissa Swartz told “Dateline” that Conley, who had been working in the law library at Bedford Hills Correctional Facility, first drew her attention to the document, which she described as “probably the most facially insufficient warrant I’ve ever come across.”

“They believed that that was a warrant to take her phone and look in it,” said Swartz, who specializes in post-conviction matters. “But what it needs to be is two separate warrants; one to take her phone and then one to actually search her phone.”

In 2022, Swartz filed a motion seeking to overturn Conley’s conviction that claimed ineffective assistance of counsel and raised a series of issues about her defense. Among them was Pelli’s failure to challenge the warrant on the grounds that it was overbroad. In a hearing on the matter, Pelli acknowledged the error and said he had failed to recognize it as an issue at the time.

The district attorney’s office opposed the challenge and a judge denied the motion, writing in a 2024 ruling that because there was no conviction in the first trial, the matter was moot.

But Swartz appealed, and in January, the court ruled in Conley’s favor, stating that Pelli’s failure was “sufficiently egregious and prejudicial as to compromise her right to a fair trial.” 

The fact that there had been a mistrial didn’t prevent Conley from pursuing the ineffective assistance claim, the ruling states, noting that the failure to block the warrant in the first trial led to the introduction of cellphone evidence in the second.

Conley was released days after the appeals court issued its ruling. 

The ruling does not address the evidence uncovered from Conley’s cellphone. It states only that in their warrant seeking the device and its contents, authorities did not spell out what they were looking for in connection with Mary Yoder’s death.

Swartz told “Dateline” that her role was not to solve the crime and that the effort to overturn Conley’s conviction had not sought to establish her innocence.

“We are making sure that the criminal justice system is working correctly,” she said. “That’s important for people that commit crimes, and that’s important for people who have been wrongfully convicted of committing crimes.”