A 24-year-old Mohawk Valley woman was sentenced to 23 years in prison by an Oneida County Court in New York on Thursday for killing her boss.

Kaitlyn Conley was convicted back in November by a jury which found her guilty of first-degree manslaughter, but not second-degree murder in the death of 60-year-old Mary Yoder in 2015.

Conley was working as a receptionist at the chiropractic office of Yoder and her husband William Yoder in Whitesboro when she poisoned Yoder with an anti-inflammatory drug called colchicine.

This drug is particularly used to treat gout and has a number of side effects that include inducing a burning, tingling feel on the skin, making it difficult to breathe when exercising, fever, swelling on the face, eyelids, mouth, lips, or tongue, muscle weakness, and peeling of the skin.

After being poisoned, Yoder spent some 48 hours in hospital. She suffered severe pain, vomiting and diarrhoea before she died.

However, Conley maintained she was innocent and plans to file an appeal.

Yoder’s son, Adam Yoder, was Conley’s ex-boyfriend, and he blamed himself for his mother's death in a statement before Conley was sentenced.

According to a report in NBC-affiliated television station WKTV, Adam said, “Make no mistake. As much as I hate her, which is more than I ever thought I would be capable of hating anyone, I hate myself infinitely more. I introduced her to my family. I got her a job with my parents. And if I hadn't done those things, my mother would still be alive.”

He added, "Since this investigation began, I have seen three psychologists and one psychiatrist. I've now been prescribed multiple medications for sleep, for major depression, for severe anxiety and for PTSD, all of which have been prescribed for one simple reason: self hatred.”

Yoder’s husband William said, “We had to helplessly watch her die again and again and again. The pain of that last day will haunt me and my family for the rest of our lives.”

“Every day I felt blessed and grateful that she was in my life and that she had chosen to share a life with me. And she often told me she felt the same. We felt like the two luckiest people in the world to have found each other. After 40 years together we were still deeply in love, still delighted just to spend time together," he said, according to a report in Spectrum News.

An emotional Liana Hedge, Yoder’s eldest daughter, talked about the difficulty of handling her children along with the grief of her mother’s death.

Hedge said, “The hardest thing I have ever had to do as a parent was to sit my children down for the second time in a month and tell them their grandmother died again. I watched my 6-year-old’s heart break in front of me....his lips shaking, he asked, ‘we don't have a grandma anymore?’”

However, there were some relatives of Yoder who spoke in favor of Conley. Yoder’s sister, Jeannine King, said, “Although I believe she is innocent, I must respect the decision of our courts. With that being said, I'm writing to you to plead for mercy and leniency.”