The case of

Mary Yoder


Mary Yoder

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Date of Death

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Incident Location

Chiropractic Family Care Clinic in Whitesboro, NY

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Mary Yoder – A Beloved Matriarch Dies Under Suspicious Circumstances

Mary Yoder was murdered by someone she thought she could trust. Kaitlyn “Katie” Conley was an employee Mary considered a friend who also had an on-again-off-again relationship with Mary’s son, Adam. Kaitlyn wrote a letter trying to frame Adam for the murder, but the truth eventually came out.

Mary Yoder’s Life And Sudden Death

Mary Yoder and her husband of 38 years, William Yoder, made their living as chiropractors. For 28 years, they had run the Chiropractic Family Care Clinic in Whitesboro, NY. Although Mary was 60-years-old, she led a very active lifestyle, caring for the couple’s three children and grandchildren while often putting in 10-hour workdays at her clinic. She had a fulfilled career life and a beautiful family. Many friends and family described her as the epitome of health, so when Mary became suddenly ill and died within 48 hours, everyone was shocked.

A Timeline Of Mary Yoder’s “Illness” And Death

On July 20, 2015, Mary Yoder had a full schedule of patients at the chiropractic clinic. Mary felt fine that morning and even found time to visit her 90-year-old mother during lunch. But around 4:30 pm, Mary started feeling nauseous and began throwing up while also experiencing abdominal pain and diarrhea. At 6:30 pm, Mary left the clinic to go home. She continued feeling sick during the night, and William woke up early the following day to find Mary pale and exhausted.

Bill called their daughter, Liana, who was a physician, for advice. She told her father to get Mary to the hospital as soon as possible. All the doctors that saw Mary were baffled by her condition. At first, the doctors suspected infection was causing Mary to be ill, but that didn’t seem like the correct diagnosis. Mary’s health deteriorated, with her coding three times at the hospital. On July 22, 2015, Mary Yoder died less than 48 hours after becoming ill.

Criminal Investigation

Liana asked the medical examiner to do a toxicology test, and the results were startling. It showed that Mary overdosed on colchicine. Often used to treat gout, a larger dose of colchicine causes the major organs to stop, resulting in cardiac arrest. Mary, who didn’t suffer from gout, would have had to take 40-60 gout pills to kill herself, so detectives believed someone had intentionally poisoned Mary Yoder.

Who would want to kill this beloved community doctor? As is often the case, suspicion turned on the husband. After Mary’s death, Bill didn’t grieve quite as much as some thought he should. Then it was learned he started seeing his widowed sister-in-law not long after Mary’s death. But Mary and Bill were complete opposites. While Mary was outgoing, Bill was reserved and quiet. Could Bill have killed Mary for his own gain?

Then, an anonymous letter appeared on the same day at both the Medical Examiner’s Office and the Oneida County Sheriff’s Department. The letter stated that Adam Yoder, Mary’s son, had given her the colchicine because he was angry at her and wanted an inheritance. The letter told detectives they could find a vial of colchicine under the passenger seat of Adam’s Jeep.

Investigators brought Adam in, searched the Jeep, and found the vial. Also found in the Jeep was a receipt for the colchicine purchase with an email address – [email protected]. Why would Adam want to kill his own mother? However, it couldn’t be Adam – he had an alibi. Five days before Mary’s death, Adam had gone to Long Island to visit his sister, only returning when he had heard about his mother’s death. Was someone trying to frame him?

An Unexpected Suspect Was Connected To Mary Yoder’s Death

When the vial was examined, investigators found something interesting – it contained both the fingerprints and DNS of Kaitlyn “Katie” Conley, the receptionist at Mary’s chiropractic office and Adam’s on-and-off girlfriend. Katie admitted to sending the anonymous letter to the Oneida County Sheriff’s Office when she was brought in for questioning. But she said she did it because she loved Mary and feared Adam. She claimed she had broken up with Adam when he became abusive. After all, Katie was so close to Mary that she had been listed as a loved one in Mary’s obituary. Could she do something like that, and if she did, what was her motive?

Investigators learned that it was Katie who had signed for the vial of colchicine at the clinic, which would explain why her fingerprints and DNA were on it. But signing for delivery to the office was part of her job. What about that email? It had been created on a computer at the clinic and been accessed via Katie’s phone, yet it had never been accessed by any of Adam’s devices.

The colchicine was also purchased with a gift card – one bought by Katie. And detectives found she researched colchicine on her phone. It turns out Katie and Adam had had a tumultuous relationship. She had charged him with rape and even given him a supplement in 2015 to help him focus on school, but he had experienced symptoms similar to his mother’s.

Katie Conley’s Arrest And Further Suspicions

With all this evidence, the police arrested Katie for second-degree murder and she went to trial in 2015. Prosecutors said Katie had done it to win back Adam. And if that was the case, it worked for a while. After Mary’s death, the couple reunited, only to break up again. The defense attorney pointed the finger at Bill, saying he had an opportunity to place the colchicine in Mary’s protein shake before she went to work on the morning of July 20. If he killed Mary, he would be free to be with her sister. But phone records showed little contact between Bill and Mary’s sister before her death.


The first trial resulted in a hung jury, but in the second trial, Bill testified that he cried for hours after seeing his wife in pain, then losing her. Liana testified that her mother’s death completely broke her father. Someone from the company where the colchicine was purchased testified she had talked to a soft-spoken young female at the clinic about the order.


Katie was found guilty of first-degree manslaughter on November 6th, 2017, and sentenced to 23 years in the Bedford Hills Correctional Facility for Women. Katie maintains her innocence, still contending that Adam poisoned his mother. Even after the verdict, some of Mary’s family members remain torn, believing that this is something of which Bill might have been capable.

Katie Conley isn’t eligible for parole until 2037.

Frequently Asked Questions

What happened to Mary Yoder?

A toxic relationship between her son and his on-off-girlfriend led to the fatal poisoning of chiropractor Mary Yoder. A homicide investigation showed that she was poisoned with colchicine.

What happened to Kaitlyn Conley?

In January 2018, Oneida County Court sentenced the 24-year-old to 23 years in prison.

When Will Kaitlyn Conley Get Out Of The Prison?

She will be eligible for parole in 2037.

Did Bill Yoder Kill his Wife?

Although Kaitlyn Conley was sentenced for Mary Yoder’s murder, there were some suspicions that William Bill Yoder was involved in his wife’s murder. Such suspicions were fueled by the fact that he started a relationship with his widowed sister-in-law not long after Mary’s death. Mary Yoder’s three sisters still believe that Katie Conley is innocent. and that Bill Yoder should be in prison instead.