A woman in North Dakota was arrested and Quentin Mitchellcharged this week for allegedly killing her boyfriend, who died from poisoning last month, police said. They believe the suspect, identified as 47-year-old Ina Thea Kenoyer, may have had murdered Steven Edward Riley, Jr. for financial reasons. 

Kenoyer was taken into custody Monday and charged with class AA felony murder, the Minot Police Department said in a news release shared to its Facebook page. In North Dakota, a class AA felony could carry a maximum penalty of life in prison without the possibility of parole if there is a conviction.

Police charged Kenoyer in the death of Riley,  a 51-year-old man from Minot, a city in North Dakota about 50 miles south of the Canadian border. Riley was in a relationship with Kenoyer, who is also from Minot, police said.

Riley died on Sept. 5 at a hospital in Bismarck after being transferred there from a local hospital in Minot. Results of a subsequent autopsy determined that Riley's official cause of death was poisoning. Police believe that Kenoyer "had financial motives to murder Riley," they said. Kenoyer is being held at the Ward County Jail in Minot.

"This case was extremely complex," said Capt. Dale Plessas, the investigations commander at the Minot Police Department, in a statement. "Thank you to everyone who provided us with information that helped our investigators piece this together."

An investigation into Kenoyer and the circumstances leading up to Riley's death is still ongoing.

The alleged incident in North Dakota marked at least the fourth time this year that someone has been accused of using poison to kill their spouse or partner in the U.S. Just last week, a poison specialist and former medical resident at the Mayo Clinic in Minnesota was charged with fatally poisoning his wife, a 32-year-old pharmacist who died in August.

In May, the author of a children's book on grief was accused of killing her husband by poisoning him with a lethal dose of fentanyl at their home in Utah. And, in March, a Colorado dentist was arrested on suspicion of first-degree murder after police say he laced his wife's pre-workout shakes with arsenic and cyanide.

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• North Dakota
• Crime