A Colorado dentist accused of killing his wife by poisoning her protein shakes now faces a new charge for allegedly attempting to get a fellow inmate to murder a detective investigating his homicide case.    

James Toliver Craig, 45, was charged with solicitation to commit murder in the first degree and solicitation to commit perjury in the first degree, the 18th Judicial District Attorney's Office announced in a social media post. 

Craig was previously arrested and charged with first-degree murder in the death of his wife of 23 years, Angela Craig. He pleaded not guilty to that charge. 

Angela was a 43-year-old mother of six, who died in March 2023 of poisoning from cyanide and tetrahydrozoline, the latter a substance found in over-the-counter eye drops, according to the coroner. 

DENTIST ACCUSED OF FATALLY POISONING WIFE HIT WITH NEW CHARGES AS LAWYER QUITS

James Craig in family portrait

Angela and James Craig in a family portrait. James has been charged with first-degree murder for allegedly poisoning his wife. (Facebook)

Authorities believe Craig allegedly tried to get another inmate in the Arapahoe County jail to kill an Aurora police detective, who was working on the investigation into Angela's 2023 death, according to court records and "multiple sources familiar with the investigation," KUSA reported. Joe Moylan, an Aurora police spokesman, told CBS News that the intended victim of the alleged plot was an Aurora detective.

The other inmate has not been accused of any wrongdoing related to the alleged plot to kill the detective, KUSA added.

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Craig was previously accused in May of asking a fellow jail inmate to plant letters in his garage and his truck to make it look like his wife was suicidal, offering money to pay the inmate's bond in order to be released from jail or perform free dental work in exchange for planting the letters, police said. 

The inmate, who reported the incident to authorities, believed the letters that were meant to appear as if Angela had written them were actually written by Craig. 

COLORADO DENTIST ACCUSED OF POISONING WIFE TRIED TO GET FELLOW INMATE TO PLANT FAKE SUICIDE NOTES: POLICE

James Craig and wife smile in selfie photo

Colorado dentist James Craig, right, is accused of fatally poisoning his wife and the mother of his six children, Angela Craig. (Facebook)

Craig allegedly created a secret email account and searched online for things like "How to make murder look like a heart attack" and "How to make poison," just days before his wife searched for symptoms she was experiencing like vertigo, shaking and cold lips, according to police. 

Angela went to a hospital three times before her death after becoming faint and dizzy, according to the arrest affidavit. 

Authorities said Craig also researched and purchased "undetectable poisons," and he ordered a shipment of potassium cyanide to his dental practice.

"In totality, this investigation has proven that James has gone to great lengths to try and end his wife's life," Aurora police Detective Bobbi Olson wrote in the affidavit. 

However, Craig's lawyers claimed there is no direct evidence that he put poison in his wife’s shakes and have accused Olson of being biased against him.

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James Toliver Craig

James Toliver Craig in a mugshot provided by the Aurora Police Department. (Aurora Police Department)

Craig also allegedly flew his orthodontist lover from Austin to Denver while his wife was dying, and the two reportedly exchanged "sexually explicit emails," according to the arrest affidavit. 

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Angela Craig told her sister Toni Kofoed several times over the past 16 years that she planned to leave her husband, but he always convinced her to stay. The couple was on the verge of declaring bankruptcy for a second time, according to the documents.

Kofoed told police that Craig had "multiple affairs with several women" and that he had drugged his wife about five years earlier because he had planned to die by suicide and didn't want her to stop him.

COLORADO DENTIST ACCUSED OF POISONING WIFE'S PROTEIN SHAKES TO START NEW LIFE WITH LOVER

James Craig wearing a face mask with a whole in it

Two photos of dentist James Oliver, who is accused of murdering his wife, Angela Craig. (Facebook)

Craig's trial for the murder of his wife, originally scheduled to start on Nov. 21, was delayed, as his defense counsel moved to withdraw from the case due to a "professional conflict," according to the 18th Judicial District Attorney’s Office. 

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The next hearing for Craig's case is scheduled for Dec. 16, according to the 18th Judicial District Attorney's Office.

Fox News' Christina Coulter contributed to this report