A Boone County jury found Steven Mackovich guilty Wednesday of killing his friend Charles Johnson.
The pair left their Fort Atkinson, Wisconsin homes on April 24, 1980 for a road trip to Alabama, but the next day, only Mackovich returned.
Johnson's body was found in a Boone County cornfield on May 3, 1980. He had been stabbed 41 times. Prosecutors said Mackovich is the only one who had the opportunity and motive to kill Johnson, but defense attorney Dennis O'Sullivan contended authorities have no evidence to prove his client killed Johnson.
His sentencing is set for March 5.