CHISHOLM, Minn. - Investigators in this Iron Range town spent more than three decades determining who didn't kill Nancy Daugherty, a well-liked aide at a local nursing home who was found strangled in her bed in the summer of 1986.
Police chief after police chief inherited the unsolved mystery. More than 100 people offered up DNA samples for comparison to what was found at the crime scene, including one that required authorities to travel to Texas to collect. Tens of thousands of dollars were offered in reward money.
But there has only ever been one arrest in the case — Michael Allan Carbo Jr., who was recently convicted of murder in the first degree while committing a sexual act.

Carbo was heading into his senior year at Chisholm High School at the time of the murder. He lived less than a mile from Daugherty then, and 34 years later remained in the same city.
"The amazing thing to the whole story is the fact that [Carbo] was able to live in that community and never say a word to anybody," said former police chief Scott Erickson. "All the publicity, all the reward money we had out there, he never said a word to anybody. What are the odds to that? Slim."
Still, Erickson, who has since moved to Washington, has no doubt that the jury convicted the right person in St. Louis County Court in mid-August, a case that still ripples through the city of 4,900 people.
More than a week after Carbo's conviction, some Chisholm residents were reluctant to talk about what has long been a cold case. Carbo has a vast network of family in town and friends in bars on the main drag who consider him kind and trustworthy. After his arrest, nearly two dozen people sent letters to the court in support of their friend, uncle, stepson. They asked for reasonable bail and promised that Carbo was not a risk to the community.
This is the only significant crime on his record.