A Colorado man suspected of poisoning his wife has been arrested on suspicion of first-degree murder.

The 45-year-old Aurora man, James Toliver Craig, was arrested and booked into jail early Sunday, the Aurora Police Department said.

The arrest came four days after the suspect, a dentist, drove his 43-year-old wife to a hospital because she was complaining of headaches and dizziness, police said.

The woman’s condition rapidly deteriorated and she was declared brain dead a short time later. Doctors removed her from life support early Sunday morning, police said.

Aurora Police Division Chief Mark Hildebrand said in a statement that it was a “heinous, complex and calculated murder” but did not release further details.

Craig works as a dentist in Aurora.