Connor Bowman searched for information on "lethal doses" prior to wife Betty Bowman's poisoning death, warrants say

ROCHESTER, Minn. — Newly-released warrants from the Rochester Police Department shows how they built the case against former Mayo Clinic resident, Connor Bowman, for the death of his wife, Betty Bowman.

Friends told police that Connor and Betty Bowman were in an open relationship, but Connor had developed an emotional connection with another woman, and were heading towards divorce.

That's when investigators say he started his research. On Connor Bowman's University of Kansas laptop, where he worked as a poison specialist, he searched for "poisons" and "lethal doses specifically for individuals weighing approximately 120 pounds."

MORE: Fmr. Mayo Clinic doctor Connor Bowman charged with fatally poisoning pharmacist wife Betty Bowman

In August, investigators say he narrowed in on a drug called Colchicine, used to treat gout, and bought some online.

At one point, Connor Bowman made his wife a "suspicious smoothie," and a friend even "joked with Betty ... that Connor might have been trying to poison" her.

The night Betty Bowman went to the hospital, Connor Bowman "surprised her with an alcoholic drink."

Over objections from Connor Bowman, an autopsy found Colchicine in Betty Bowman's system, despite no gout diagnosis.

What put the case over the top for detectives: A $450,000 life insurance payment — quickly put in Connor Bowman's ban account.

Though it is not nearly enough to cover his $5 million bond, as he remains locked up on murder charges at the Olmsted County Jail.