Chiropractor Mary Yoder died in July 2015 after being poisoned with colchicine; her receptionist Kaitlyn Conley was convicted of manslaughter in 2018, but the conviction was overturned on appeal in 2025 and a third trial is now being pursued.
Mary Louise Yoder (March 18, 1955 – July 22, 2015) was a chiropractor who ran a small practice with her husband, Bill, in Whitesboro, New York. She had been in good health until her condition declined rapidly in July 2015, and she died shortly afterward. Her relatives found the death suspicious and contacted law enforcement. An autopsy determined that Yoder had died from poisoning with colchicine, an anti-inflammatory drug, and the death was ruled a homicide.
In November 2015, the Oneida County Sheriff's Office received an anonymous letter accusing Yoder's son, Adam, of the killing. A search of Adam's jeep turned up a bottle of colchicine under a seat. However, Adam was reportedly out of town at the time of the poisoning, and he said the bottle had been planted.
Investigators turned their focus to Kaitlyn Conley, a receptionist at the Yoders' office who had previously dated Adam. Conley was charged with second-degree murder in July 2016, with prosecutors alleging she had poisoned Mary Yoder during a lunch at work. Conley acknowledged writing the anonymous letter but maintained that Adam Yoder was responsible for the poisoning. At trial, the defense pointed instead to Mary's husband, Bill Yoder, as a possible perpetrator.
Conley's first trial, held in May 2017, ended in a mistrial after the jury failed to reach a unanimous verdict. A second trial concluded in January 2018, in which Conley was acquitted of second-degree murder but convicted of manslaughter. She was sentenced to 23 years in prison.
In 2019, the U.S. Supreme Court declined to hear an appeal brought by the Utica Observer-Dispatch seeking access to juror questionnaires from Conley's trial.
In February 2025, the New York Court of Appeals overturned Conley's manslaughter conviction, ruling that evidence obtained from her cell phone had been improperly obtained and should not have been admitted at trial. The Oneida County district attorney moved to hold Conley pending a new indictment, but a county judge denied that motion, and Conley was released from prison.
As of October 2025, the Oneida County district attorney is pursuing a third trial against Conley. An appeals hearing regarding sealed evidence was scheduled for April 2026 before a judge in Rochester. The case has been the subject of media coverage including Forensic Files II, My Favorite Murder, Crime Watch Daily, Dateline NBC, and the Hulu miniseries Little Miss Innocent, in which Conley was interviewed.
Mary Yoder dies after a rapid decline in health; autopsy later determines death by colchicine poisoning, ruled a homicide.
2015-11
Oneida County Sheriff's Office receives an anonymous letter accusing Adam Yoder of the killing; a bottle of colchicine is found in his jeep.
2016-07
Kaitlyn Conley is charged with second-degree murder.
2017-05
Conley's first trial ends in a mistrial after the jury fails to reach a unanimous verdict.
2018-01
Conley is acquitted of second-degree murder but convicted of manslaughter in a second trial; she is sentenced to 23 years in prison.
2019
The U.S. Supreme Court declines to hear an appeal by the Utica Observer-Dispatch over access to juror questionnaires from the trial.
2025-02
The New York Court of Appeals overturns Conley's manslaughter conviction, ruling cell phone evidence was improperly admitted; she is later released from prison after a judge denies a motion to hold her pending a new indictment.
2026-04
A date is set for arguments before an appeals judge in Rochester regarding sealed evidence, as the district attorney pursues a third trial.
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The Twisted Case of Mary Yoder
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Mary Yoder
VICTIM
Chiropractor who died in July 2015 of colchicine poisoning, ruled a homicide.
Kaitlyn Conley
CONVICTED
Former receptionist at Yoder's practice; acquitted of second-degree murder but convicted of manslaughter in 2018 (sentenced to 23 years); conviction overturned on appeal in February 2025 and a third trial is being pursued.
Roles reflect public records and court outcomes at the time of writing — supporting citations are on file under Sources.
Chiropractor Mary Yoder died in July 2015 after being poisoned with colchicine; her receptionist Kaitlyn Conley was convicted of manslaughter in 2018, but the conviction was overturned on appeal in 2025 and a third trial is now being pursued.
Where did the killing happen?
Whitesboro, New York.
Who was convicted?
Kaitlyn Conley (Former receptionist at Yoder's practice; acquitted of second-degree murder but convicted of manslaughter in 2018 (sentenced to 23 years); conviction overturned on appeal in February 2025 and a third trial is being pursued.).
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