AURORA, Colo. (KDVR) — An Aurora dentist was accused of poisoning his wife to death this week.

James Toliver Craig, 45, was arrested on a first-degree murder charge Sunday.

According to the Aurora Police Department, Craig drove his 43-year-old wife to a local hospital around 8:45 p.m. Wednesday after she complained of severe headaches and dizziness.

Her condition quickly deteriorated, and she was placed on a ventilator in an intensive care unit.

She was declared medically brain dead shortly after that.

According to APD, an investigation by the Major Crimes Homicide Unit revealed the woman had been poisoned.

APD Division Chief Mark Hildebrand called it a “heinous, complex and calculated murder.”

A warrant for first-degree murder was obtained early Sunday morning after doctors decided to take her off life support.

Craig has had his dental practice in Aurora, which is a part of Summerbrook Dental Group, for more than a decade. In his biography on the website, it says “(He) and his wife Angela are the proud parents of six great kids.”

While patients and those who used to work for Craig spoke with FOX31 off-camera and said he was normal, always professional, happy and this is beyond shocking.

The investigation was still ongoing, and anyone with information was asked to contact the Metro Denver Crime Stoppers at 720-913-7867.