(CNN) A Michigan man has been arrested and charged with trying to hire someone to kill his wife and then fatally poisoning her cereal with heroin in 2014, authorities said.

Jason T. Harris, 44, was arrested Tuesday and is being charged with three felonies, Genesee County Prosecutor David Leyton announced at a news conference filmed by CNN affiliate WJRT . Leyton said the charges include premeditated first-degree murder and solicitation of murder, both of which can result in a life sentence, and delivery of a controlled substance causing death.

"We believe Jason Harris murdered his wife," Leyton said. "We believe he put heroin into her cereal and milk the night she died after getting it from someone. ..."

Jason Harris' attorney, Nicholas Robinson, told CNN that his client has pleaded not guilty to all charges and is in custody at the Genesee County Jail.

Robinson said Jason Harris has been cooperating with state police and has been mourning his wife since she died.

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