A Minnesota doctor accused of spending days researching a poison before his wife was poisoned and John Caldwellkilled had his charge upgraded to first-degree murder after being indicted by a grand jury.

Dr. Connor Bowman, 30, was initially arrested and charged with second-degree murder in October, in connection to the death of his wife, Betty Bowman. She died on Aug. 20,  four days after she was taken to the hospital with “severe gastrointestinal distress and dehydration where her condition deteriorated rapidly.

The Olmsted County Attorney's Office on Friday announced that a grand jury indicted Bowman, a former poison control specialist, on first-degree murder, premeditated and with intent charges.

If convicted, Brown could be sentenced to life in prison.

Drugged to death:A poison expert researched this drug before his wife died from it. Now he's facing prison.

Suspicious death

Betty Bowman was hospitalized in mid-August after suffering from gastrointestinal distress. After her death, investigators began looking into the case after a medical examiner raised concerns about suspicious circumstances surrounding her death.

Investigators alleged that Connor Bowman had intentionally poisoned his wife with colchicine, a medicine used to treat gout, after days of researching the drug.

After her death, Connor Bowman attempted to obstruct an autopsy and demanded that she be cremated immediately, police said.

Connor Bowman attempted to have his wife's autopsy canceled and asked to have her cremated. He told medical staff his wife had a rare immune condition called hemophagocytic lymphohistiocytosis or HLH. However, hospital tests did not substantiate that. He also made that claim to multiple people and included it in her obituary, prosecutors alleged.

The medical examiner found that she died from the toxic effects of colchicine, a drug used to treat gout, and marked her death as a homicide.

According to the criminal complaint, a search of Connor Bowman's computer history showed that he had researched the drug and how much a lethal dose would be for his wife based on her weight a week before she was hospitalized.

He also looked up whether internet browsing history could be used in court as well as sodium nitrate, a chemical compound that can limit oxygen transport through the body, the complaint said.

Connor Bowman and wife were weighing potential divorce, police say

Detectives said they spoke with a woman who said the couple were in the middle of divorce discussions because of "infidelity and a deteriorating relationship," the complaint said.

Police also learned Bowman was the beneficiary of his wife's life insurance policy with a payout in the hundreds of thousands. At his house, investigators found a bank deposit receipt for the amount of $450,000, records show.