Private database DNA leads to 'first-of-its-kind' trial in 1986 Minnesota cold case

With the case involving complicated and novel DNA issues, it may take a jury up to four weeks to hear the case of Michael Carbo in the rape and beating death of Nancy Daugherty.

Michael Carbo
Michael Carbo

DULUTH — A nearly four-week trial has been scheduled for the Chisholm, Minnesota, man accused of raping and killing a woman in 1986.

Michael Allan Carbo Jr., 53, was arrested and charged in July 2020 after DNA evidence and privately maintained genealogy databases allegedly helped identify him as the man responsible for the death of 38-year-old Nancy Daugherty.

Nancy Daugherty
Nancy Daugherty

Judge Robert Friday, who previously affirmed the first-of-its-kind investigation in Minnesota, scheduled jury selection to begin June 1 in State District Court in Hibbing. The presentation of evidence and arguments may continue as late as June 24.

Private DNA databases searched

Daugherty, a mother of two, was found dead inside her Chisholm home on July 16, 1986. She had been sexually assaulted, beaten and strangled, with police indicating there were signs of struggle both inside and outside the residence.

Over the years, authorities said "well over" 100 DNA samples from potential suspects were tested, but none resulted in a match. It was in late 2019 and early 2020 that Chisholm police made the decision to contract with Parabon NanoLabs, a company based in the state of Virginia, in hopes of developing new leads.


The Minnesota Bureau of Criminal Apprehension released a sample of the suspect's semen to another company, AKESOgen, in order to develop a single nucleotide polymorphism profile, which allows experts to determine physical characteristics and ancestry of an individual. Parabon then used that profile to search privately maintained databases known as GEDMatch and FamilyTreeDNA.

Carbo had never personally submitted a DNA sample to either database, but Parabon's searches reportedly turned up several genetic relatives, leading to the development of family trees and the identification of him as a suspect. Carbo, 18-years-old at the time of Daugherty's killing, had lived within a mile of the victim and went to school with her children, court documents state.

Agents collect evidence from Q-tips, beer can

BCA agents in July 2020 started surveillance of Carbo, retrieving trash bags he had thrown into a dumpster outside his Chisholm apartment building. Taking swabs of paper towels, facial tissues, Q-tips, a beer can and a SlimFast bottle, analysts said they were able to develop a DNA profile that was consistent with that of the suspect from 1986.

Agents then approached Carbo and asked him to voluntarily submit a sample, which again confirmed the match, according to court documents.

Judge Friday in November rejected constitutional challenges to the investigation, likely setting a precedent for police in the state to continue tapping into genetic databases in hopes of identifying suspects in decades-old cold cases.

Friday acknowledged the potential privacy pitfalls involved in the tactic, but found no violations of state or federal law. He concluded that police are free to test DNA that is "abandoned" at a crime scene and compare it against samples submitted to a database by consenting individuals.

Carbo, who is charged with intentional second-degree murder, has not yet filed notice of any defenses he may raise at trial. He remains jailed on $1 million bail.

The case is being prosecuted by Assistant St. Louis County Attorney Chris Florey. Carbo is represented by public defender J.D. Schmid.

Tom Olsen has covered crime and courts for the Duluth News Tribune since 2013. He is a graduate of the University of Minnesota Duluth and a lifelong resident of the city. Readers can contact Olsen at 218-723-5333 or
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