DENVER — The murder trial of a Colorado dentist accused of killing his wife by poisoning her protein shakes and later trying to pay someone to kill the lead investigator on the case will begin with opening arguments Tuesday.

James Craig, 47, allegedly used cyanide and tetrahydrozoline, an ingredient in over-the-counter eye drops, to kill his wife of 23 years, Angela Craig, two years ago in suburban Denver.

Craig has pleaded not guilty to several charges, including first-degree murder.

Prosecutors say that Craig allegedly purchased arsenic around the time of his wife’s symptoms — dizziness and headaches that perplexed doctors — and that after his initial attempts to poison her failed, he ordered potassium cyanide.

They also said Craig searched Google for “how to make a murder look like a heart attack” and “is arsenic detectable in an autopsy,” and that he tried to make it appear his wife had killed herself.

Angela Craig, 43, who had six children with James Craig, was hospitalized several times. After the first time, she can be seen on home surveillance video accusing her husband of implying to medical staff that she was suicidal.

“It’s your fault they treated me like I was a suicide risk, like I did it to myself, and like nothing I said could be believed,” she said to her husband on the video.

After Craig’s arrest in 2023, prosecutors alleged that he offered a fellow jail inmate $20,000 to kill the case’s lead investigator and offered someone else $20,000 to find people to falsely testify that Angela Craig planned to die by suicide.

In addition to first-degree murder, Craig has pleaded not guilty to the other charges, including solicitation to commit murder and solicitation to commit perjury.

Craig’s attorneys have questioned the reliability of the inmate’s claims, said the police were biased against the dentist and that tests of the protein shake containers didn’t reveal signs of poison.

Around the time of his arrest, prosecutors said Craig was experiencing financial difficulties and appeared to be having an affair with a fellow dentist, though they have not yet described a motive in his wife’s death.

Craig remains in custody, according to jail records.