Vet’s New Wife Accused of Poisoning Him with Animal Euthanasia Drugs

Does Amanda Chapin Fit the Psychological Profile of Poisoner?

Joni E. Johnston, Psy. D.
5 min readJan 10, 2023
copyright free, courtesy of Lafayette County Sheriff’s Department

Through no fault of his own, 2022 was a horrible year for Wisconsin veterinarian Gary Chapin.

2022 started on a high note. The new year found Dr. Chapin in the ecstasy of a romance with a woman he had met on the internet a year earlier; Amanda Ruiz. There was a twenty-year age gap between the two — she was fifty to his seventy — but neither one batted an eye over it.

None of Dr. Chapin’s three children were as fond of their dad’s new love. They thought she was suspiciously secretive about her past. They didn’t trust her; one of his daughters accused Amanda of lying and manipulating her father. But Dr. Chapin was smitten. In March, they tied the knot, and Amanda Ruiz Grant became Amanda Chapin.

The honeymoon period was short-lived. According to the Wisconsin State Journal, shortly after the two married, the new Mrs. allegedly forged the signature of her new stepson on a power-of-attorney document. Cole Chapin received a text from his father in May, stating that he would have medical power of attorney should he need to make emergency medical decisions. However, on July 18, 2022, Cole was presented with a document that listed Amanda Chapin as the first power of attorney and him as the second. And what a surprise to see his own signature on the amended document, one that he was sure he had never laid eyes on.

Of course, you’re probably wondering why the power of attorney issue was even raised. On July 18, Dr. Chapin had his morning coffee with his new bride, something she lovingly prepared for him each day. However, when he went to stand up, he had a severe bout of vertigo. Whenever he moved, it felt like the room was spinning around him. He tried to self-medicate and felt “five times worse.” So he went to the hospital. Doctors evaluated him, but they were stumped. He came home without a diagnosis.

Around this time, Mrs. Chapin became concerned about her new husband’s health. He was not exactly a spring chicken, she told him. He was already having health problems; look at his recent trip to the emergency room. In fact, before Dr. Chapin went to the hospital on July 18, Amanda Chapin had tried to convince him that he was experiencing stroke-like symptoms. She’d told him half of his face was slack, and he was slurring his speech. But when he’d made his way to the bathroom mirror, he saw no evidence of either.

What if his vertigo was a symptom of something more serious, like a stroke? What would happen to her if he died? The least he could do was amend his house deed so she would get the home if he died. By this time, Dr. Chapin felt fit as a fiddle again. But he could see the logic in his wife’s argument. While vertigo typically wasn’t dangerous, he knew it could be associated with strokes. So he accommodated his wife’s wishes.

Euthanizing Dogs and Doctors?

In early August, his symptoms returned. He spent the night of August 7 at the hospital. The symptoms weren’t as severe this time, but Dr. Chapin was concerned since he didn’t know what was causing them. Perhaps the hospital staff could help him get an accurate diagnosis. Still no answers.

On August 21, around 9:30 a.m., Dr. Chapin drank his last cup of coffee with his wife of five months. The pair drank their java on a bench outside their front door. That was the last thing he remembers.

He woke up four days later from a coma, having narrowly escaped the jaws of death. He had been transported to the hospital by Emergency Medical Services after collapsing; his wife reportedly called 911 around 12:30 p,m. Dr. Chapin later said his “loving” wife left him outside and unresponsive for hours before calling for help. Investigators later discovered that Ms. Chapin may have spent that time perusing her husband’s emails, forwarding several of them between Mr. Chapin and his children or his attorney to her account.

Fortunately, this hospital stay shined the light on what was going on for Dr. Chapin and the doctors taking care of him. Toxicology reports from all three hospital admissions showed that Dr. Chapin had the same drugs in his system that he used to euthanize terminally ill or suffering animals in his vet clinic; he had even provided this service for his wife’s dog. His blood work on August 21 showed massive amounts of barbiturates in his system. Based on his symptoms (and later confirmed by blood tests), he believed that his wife had poisoned him with Primidone (an anti-seizure medication) the first two times. Then, when that didn’t do the trick, she graduated to the barbiturate Phenobarbital.

He was lucky to be alive.

The End of a Toxic Marriage

The Chapins’ brief marriage had been stormy. Dr. Chapin had begun to suspect that his new bride was less interested in him than she was in his money. Fortunately, he had conveyed his belief that he was being used as a “sugar daddy” to his kids, verbally and through phone messages. His son, Cole, got a restraining order against his stepmother before his dad even woke up from his coma.

Amanda Chapin knew the marriage was over. She hurriedly left her husband’s house before he was released from the hospital, leaving behind some of her stuff but, oddly enough, taking her mortar and pestle. Her husband knew whoever had poisoned him must have ground up the pills into a powder, and that’s what a mortar and pestle does.

On September 1, 2022, Ms. Chapiin violated the restraining order against her by emailing her estranged husband a suicide note. The gist of it was that she was innocent, had nothing to do with her husband’s health problems, and was only guilty of one thing; “loving you SO, SO, SO, SO, much.” She was killing herself, the note said, because his children were going to “destroy” her.

First responders found her unconscious in a hotel room and rushed her to the hospital. She recovered and was arrested on December 28. She has been charged with first-degree attempted homicide.

On September 2, Dr. Chapin filed for divorce.

The Psychology of a Poisoner

To date, Amanda Chapin has not been of any crime. I’m unaware of her criminal history, and I’ve looked. Her attorney has proclaimed her innocence and said she is more than ready to face her accused in a court of law.

But there is something about Amanda Chapin that reminds me of other poisoners. In my experience, they share similar personality traits; sneaky, self-centered, and manipulative. They rarely deal with conflict directly, maneuvering through deviousness and deceit. Regarding motive, I’m astonished at how often greed is the poisoner’s driver and how often they’ve left behind a trail of financial misdeeds.

I’m sure we’ll learn a lot more as the wheels of justice turn. But I have a feeling 2023 is not going to be Amanda Chapin’s year.

As always, thanks for reading the Mind Detective. Please feel free to pass this along to your true crime friends. I hope 2023 is off to a great start. If there’s a case you’d like to me to cover, please email me and let me know.

Originally published at on January 10, 2023.



Joni E. Johnston, Psy. D.

Forensic psychologist/private investigator//author of serial killer book. Passionate about victim’s rights, the psychology of true crime, and criminal justice.