A 37-year-old Minneapolis homicide has been solved with a confession, authorities said Thursday.

Michael J. Husten, 61, who is serving time in Stillwater prison for an unrelated robbery, admitted that he killed Roger Haugen by hitting him in the head with a stereo receiver on Feb. 8, 1975, according to second-degree-murder charges filed Monday in Hennepin County District Court.

"This case is a classic example of our oft-spoken commitment to never let an unsolved homicide investigation end," County Attorney Mike Freeman said in a statement announcing the charge. "The county attorney's office and our law enforcement partners continue to work on unsolved homicides until they are solved."

According to the criminal complaint and Star Tribune reports in the days after the killing:

Hours before the crime, police were sent to Haugen's apartment in the 3600 block of Nicollet Avenue S. on a disturbance report. When they arrived shortly after 2:20 a.m., officers spoke to both men.

Later, police were sent to Hennepin County Medical Center about a man who had been left there with a severe head injury suffered at his apartment. Haugen, 24, died at the hospital the next day.

Husten had been a suspect right from the time Haugen died, but evidence had been lacking until his confession last year to investigators from the Minnesota Bureau of Criminal Apprehension.

Specifically, he told police that he picked up a stereo receiver and smashed Haugen's head during a fight.

Husten is currently serving a sentence for robbery and was expected to be released in October.

PAUL WALSH