Woman Poisoned Boyfriend to Death Thinking He'd Inherited $30M. Then She Found Out It Was All a Scam

Ina Thea Kenoyer has pleaded guilty to murdering her longtime boyfriend, Steven Edward Riley Jr., by poisoning him with antifreeze

The North Dakota man believed he had inherited $30 million.

So did his girlfriend.

Soon after, he was dead.

Only later was it revealed that there was no such inheritance.

Police found a bottle of Windex filled with what investigators believed was antifreeze in the couple’s living room.

A medical examiner later determined that Steven Edward Riley Jr. had died by poisoning, per police.

On Wednesday, May 29, Ina Thea Kenoyer pleaded guilty to murdering her longtime boyfriend, per Minot Daily News, KFYR TV and KXNET.

At the pretrial hearing, the woman in her late 40s from Minot, N.D., paused before entering her plea, according to Minot Daily News.

“Guilty,” she said, leaning toward the courthouse microphone.

Kenoyer faces up to life in prison without parole, per KFYRTV.

Related: N.D. Woman Accused of Poisoning Boyfriend with Antifreeze Hours After He Inherited $30 Million

The Minot Police Department arrested Kenoyer Oct. 30, 2023, charging her with the Class AA felony murder of her 51-year-old boyfriend, who later died at an out-of-town hospital.

Police soon determined that Kenoyer “had financial motives to murder Riley,” per the department’s press release at the time.

But investigators now say they believe the inheritance was a hoax, Minot Daily News reports.

In the arrest affidavit, obtained by KXNET, authorities say Riley planned to leave his girlfriend of about a decade.

But on September 3, as he headed toward the airport with friends to meet with a lawyer about what he believed to be his newly-acquired wealth, Riley complained of stomach pain, per court documents obtained by the outlet. His friends said he seemed drunk, although later blood tests revealed no alcohol in his system.

He began vomiting and could not walk, but, Kenoyer, who claimed she had medical training, said he had heat stroke and would recover with rest at home.

At home, investigators found a Coors Light bottle and a plastic mug with green liquid matching that of the Windex bottle, per KXNET.

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Learning from Riley’s friends that Kenoyer had previously discussed poisoning her boyfriend with antifreeze, the coroner tested for its key ingredient and found toxic levels of ethylene glycol in his system, per the outlet.

Questioned by police, Kenoyer claimed Riley had been day drinking and had gotten heat stroke.

She also suggested several explanations for the poison-like symptoms. Citing an alleged Google search, she said heat stroke may “mimic poisoning,” per court documents obtained by the outlet. There was also the possibility that he had gone into the garage, dropped a cigarette in antifreeze and smoked it anyway, she told investigators.

She proclaimed herself Riley's common law wife, and said she planned to split his newfound inheritance with his son.

But in arresting documents obtained by the outlet, she became visibly upset after investigators told her the state would not recognize her as his common law wife.

Finally, Kenoyer told investigators that she had in fact spiked his sweet tea with antifreeze before his meeting with the lawyer, per the arresting affidavit obtained by the outlet.

Kenoyer was hospitalized at State Hospital in Jamestown as part of a competency evaluation earlier this year, Minot Daily News reported.

She is scheduled to be sentenced Wednesday, Aug. 14, per the newspaper, which noted that she may undergo another psychological evaluation ahead of her sentencing.

If you are experiencing domestic violence, call the National Domestic Violence Hotline at 1-800-799-7233, or go to thehotline.org. All calls are toll-free and confidential. The hotline is available 24/7 in more than 170 languages.

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