(DENVER) — A Colorado dentist accused of killing his wife by putting poison in her protein shakes was formally charged with first-degree murder on Thursday.

James Toliver Craig, 45, appeared in an orange prison jumpsuit at the Arapahoe County District Court in Centennial, Colorado, where prosecutors filed formal charges while the defense requested all law enforcement notes to be preserved and for pretrial public comments to be limited. Craig, of Aurora, Colorado, also waived his right to a preliminary hearing within the 35-day window to give his lawyers more time.

A status hearing was set for April 7 at 3 p.m. MT.

Craig was arrested early Sunday and preliminarily charged with first-degree murder. He was ordered to be held without bond, according to a press release from the Aurora Police Department and an arrest warrant affidavit obtained by ABC News. A public defender representing Craig did not immediately respond to ABC News’ request for comment.

The charge stems from the poisoning death of his 43-year-old wife, Angela Craig, who was hospitalized three times in the span of 10 days due to severe headaches and dizziness. She was admitted to UCHealth University of Colorado Hospital in Aurora on the morning of March 15. Soon after, she had a seizure and was placed on a ventilator in the intensive care unit as her condition swiftly deteriorated. She was declared medically brain dead on Saturday afternoon and subsequently taken off life support, leaving doctors at a loss as to what would have caused her rapid decline, according to the affidavit.

The Aurora Police Department’s Major Crimes Homicide Unit was called in to investigate and ultimately discovered that Angela Craig was fatally poisoned.

“When the suspicious details of this case came to light, our team of officers and homicide detectives tirelessly worked to uncover the truth behind the victim’s sudden illness and death,” Mark Hildebrand, chief of the Aurora Police Department’s Investigations Divisions, said in a statement Sunday. “It was quickly discovered this was in fact a heinous, complex and calculated murder. I am very proud of our Major Crimes Homicide Unit’s hard work in solving this case and pursuing justice for the victim.”

In the week’s before his wife’s death, James Craig used a computer at his Aurora dental practice to create a new email address and conduct online searches related to poison, including “how many grams of pure arsenic will kill a human” and “is arsenic detectable in autopsy,” the affidavit said. He also purchased arsenic online on Feb. 23 and the shipment was delivered to his home on March 4, according to the affidavit.

Two days later, Angela Craig sent a text message to her husband complaining of dizziness and that she felt “drugged,” the affidavit said. James Craig responded: “Given our history I know that must be triggering. Just for the record, I didn’t drug you. I am super worried though. You really looked pale before I left. Like in your lips even.”

When he asked if she had “eaten anything,” Angela Craig said she “had my protein shake,” according to the affidavit. She was admitted to Centura Parker Adventist Hospital in Parker, Colorado, where she was treated and released. That same day, James Craig ordered the toxic plant extract oleandrin, but the package was “intercepted by FedEx” and never delivered, the affidavit said.

While his wife was hospitalized again from March 9 to March 14, James Craig ordered the highly lethal chemical compound potassium cyanide, which was delivered to his dental practice on March 13, according to the affidavit. When Angela Craig was hospitalized for the final time on March 15, one of her husband’s business partners told an attending nurse about the potassium cyanide delivery and how there was no need for it at their dental practice, prompting the nurse to contact police, according to the affidavit.

James Craig was known to make his wife protein shakes regularly and investigators believe he had administered the poison through these drinks, the affidavit said. The couple shared six children, according to Denver ABC affiliate KMGH-TV.

Investigators spoke to Angela Craig’s sister, who described the couple’s marriage as tumultuous and said James Craig had multiple affairs with other women, according to the affidavit. Angela Craig had also told her sister that she was drugged by her husband several years ago because he was planning to commit suicide and didn’t want her to be able to stop him. After Angela Craig’s death, her sister told investigators that James Craig “said he would not allow hospital staff to conduct an autopsy,” according to the affidavit.

Investigators learned that James Craig had told some of his employees that “his marriage was failing” and “he was in financial turmoil,” the affidavit said. After Angela’s Craig’s death, James Craig also told the Colorado Department of Human Services that his wife had been suicidal and “he had saved her many times but never reported it,” according to the affidavit. However, the affidavit noted that none of the people interviewed by investigators suggested Angela Craig had suicidal ideations.

The investigation determined that James Craig “has shown the planning and intent to end his wife’s life by searching for ways to kill someone undetected, providing her poisons that align with her hospitalized symptoms, and working on starting a new life” with another woman, according to the affidavit.

ABC News’ Jenna Harrison Esseling, Jenn Leong, Michelle Mendez, Dominick Proto, Darren Reynolds and Ben Stein contributed to this report.

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