Authorities believe that a Colorado dentist murdered his wife by lacing her pre-workout protein shakes with arsenic and cyanide so he could be with a woman he was having an affair with, according to court documents. 

James Toliver Craig, 45, was arrested early Sunday and was booked into jail on first-degree murder charges, the Aurora Police Department said. His arrest comes four days after he drove his wife, Angela Craig, 43, to a local hospital because “she was complaining of severe headaches and dizziness.”

Police said that shortly after arriving at the hospital, Craig’s condition “deteriorated rapidly.” She was then placed on a ventilator in an intensive care unit but was “declared medically brain dead a short time later.”

An investigation by Aurora police detectives revealed that Craig was poisoned and police obtained a warrant early Sunday shortly after Craig was taken off of life support.  

“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,” said Aurora Police Division Chief Mark Hildebrand. “It was quickly discovered this was in fact a heinous, complex, and calculated murder.”

According to court records, James Craig is being represented by the public defender’s office, which does not comment on cases. He is set to appear in court Thursday.

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Arsenic and potassium cyanide

With doctors unable to figure out what was wrong with Angela Craig, police began investigating James Craig after his dental practice partner, Ryan Redfearn, told a nurse that James Craig had ordered potassium cyanide even though they did not need it for their work, according to an arrest warrant.