The man arrested this week in a 1986 Chisholm homicide had lived within a mile of the victim and attended school with her children, according to a criminal complaint filed Thursday.
But charging documents do not indicate whether Michael Allan Carbo Jr. knew Nancy Daugherty personally, or how he allegedly ended up at her residence on the night she was sexually assaulted and killed. Authorities said the arrest was made possible only through DNA database analysis.
Carbo, 52, was arraigned in State District Court in Hibbing on a charge of intentional second-degree murder. Judge Andrew Peterson set his bail at $1 million.
Daugherty 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.
The victim worked as an aide in a nursing home and was a part-time bartender. She also volunteered for the Chisholm Ambulance Service as an emergency medical technician and had plans to move to the Twin Cities to further her schooling on the morning her body was discovered.
According to the complaint, Daugherty's boyfriend told police they had been out drinking the night before and that he dropped her off around 12:30 a.m. He was unable to make contact with her the next morning, so he contacted Chisholm police to conduct a welfare check.
Daugherty, a mother of two, was married at the time, but her husband, James Daugherty, was in Germany with the Air National Guard. The boyfriend, who was supposed to help her move furniture that morning, is not identified in court documents.
Daugherty's body was found in her bed, according to the complaint. Officers canvassed the neighborhood, speaking with two girls who reported hearing a struggle around 3:30 a.m., including a "call for help, screams and arguing."
According to the complaint, police recovered the suspect's DNA from both a sexual assault kit and the victim's fingernail clippings. Over the years, authorities said "well over" 100 DNA samples from potential suspects were tested, but none resulted in a match.
Periodic case reviews occurred over the years, but it wasn't until this year that a breakthrough occurred. Chisholm police consulted with the Minnesota Bureau of Criminal Apprehension and sent the suspect's DNA sample to Parabon NanoLabs, a company that analyzes public genealogy databases and helps law enforcement programs identify case leads.
Parabon was able to construct a genetic lineage for the suspect, determining that Carbo was associated with the lineage and resided in the area, according to the complaint.
Authorities last week began surveillance outside Carbo's residence in the Lincoln Square Apartments, 310 Fifth St. N.W., retrieving a bag of garbage he left in a dumpster July 23. Several items were sent to the BCA laboratory in St. Paul, with testing indicating that DNA traces were consistent with those recovered from the crime scene 34 years ago, according to the complaint.
Police approached Carbo on Wednesday, obtaining a direct DNA sample. BCA Superintendent Drew Evans said the specimen was flown to the St. Paul lab, with a positive confirmation resulting in Carbo's arrest a short time later.
Evans said at a news conference Wednesday night that it was the first cold-case in the state solved with Parabon's assistance.
Law enforcement use of genealogical databases is an emerging, yet controversial, tactic for solving decades-old homicides. Notably, Joseph James DeAngelo, the "Golden State Killer" who committed at least 13 murders and more than 50 rapes in California between 1973 and 1986, was identified and arrested in 2018 based on DNA samples provided by distant relatives for genealogical purposes.
Authorities did not provide details on the DNA profiling that led to Carbo being identified as a suspect.
Carbo was 18 at the time of Daugherty's death. Police indicated he has been a longtime resident of Chisholm and has no major criminal history. Under Minnesota law, a DNA sample must be provided when a defendant is convicted of a felony.
The complaint does not indicate whether Carbo gave any statement to investigators.
His next court appearance was set for Aug. 6.
This story was updated at 3:38 p.m. July 30 with additional details from the criminal complaint. It was originally posted at 12:25 p.m. July 30.