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Woman Charged with Murder After Allegedly Admitting to Poisoning Boyfriend after He Got $30M Inheritance

Investigators believe that Ina Thea Kenoyer fatally poisoned boyfriend Steven Edward Riley Jr. to gain part of his multi-million payout.

By Elisabeth Ford
A personal photo of Steve Riley

A North Dakota woman has been charged with murder for allegedly fatally poisoning her boyfriend in the hopes of receiving part of his multi-million-dollar inheritance.

The Minot Police Department arrested Ina Thea Kenoyer, 47, Monday in connection to the September 5 death of Steven Edward Riley Jr., 51, authorities said. According to the department, Kenoyer had “financial motives” to murder Riley.

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Prosecutors allege that Kenoyer poisoned her boyfriend with antifreeze because she thought she would receive part of a $30 million inheritance Riley was set to receive, according to an arrest affidavit obtained by NBC North Dakota-affiliate KFYR-TV.

The affidavit indicated that on September 3, friends of Riley became concerned with his health and wanted him to see a doctor, but Kenoyer insisted he was just having a heat stroke.

What did Steven Edward Riley Jr. die of? 

Riley was eventually taken to the hospital on September 4 — after authorities were called and found him unresponsive at the home he shared with his girlfriend — and died at the hospital the next day, the affidavit states, according to the The New York Times. Autopsy results determined Riley's cause of death to be poisoning, according to police. Prosecutors said that the coroner found toxic levels of ethylene glycol, an agent in antifreeze, in his system after his death. 

Riley’s friends had told police that Kenoyer had made comments about antifreeze before and after his death, according to the affidavit, KFYR reported.

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Police executed a search warrant on Kenoyer and Riley’s shared residence, where they found a capless Windex bottle containing a bright green liquid in the living room, which was suspected to be antifreeze, KX News reported. A glass cup and a mug filled with the same liquid were found in the garage.

Ina Thea Kenoyer was aware of boyfriend's inheritance and believed she was entitled to some of it

According to the station, when investigators spoke with Kenoyer, she said she knew about the inheritance Riley was set to receive and believed she was entitled to a portion of it, claiming she was Riley’s common-law wife. She added that she planned on splitting the inheritance with Riley’s son now that Riley was dead.

North Dakota does not recognize common-law marriages and authorities informed Kenoyer that she would not be receiving money, over which she allegedly became upset.

Kenoyer allegedly eventually admitted to investigators that on September 3, she made Riley sweet tea containing antifreeze, KX News reported, citing the arrest affidavit.

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According to the CDC, ethylene glycol, a key ingredient in antifreeze, has a sweet taste to it, so it can often be disguised in a sweet drink.

Kenoyer was charged with a Class AA felony murder, the most severe of its kind in North Dakota.

“This case was extremely complex,” Investigations Commander Capt. Dale Plessas said in a statement.

Plessas thanked Riley’s family and friends for coming forward with information.

“It was really the people who came forward to us that that initiated this investigation. We’re very thankful to those who stopped something that didn’t seem right [and] came and brought it to our attention,” he told KFYR.

Kenoyer is being held at Ward County Jail on a $1 million bond.

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