In a previous action on New Year's Eve 1969, Dwight and Karl stole a light plane and dropped homemade bombs that failed to explode on an area ordnance factory.

Karl made a bomb out of dynamite, 100 US gallons (380 L; 83 imp gal) of fuel oil and 1,700 pounds (770 kg) of ammonium nitrate fertilizer.

[1]The bomb was placed in a stolen van left next to Sterling Hall, a building that housed the Army Mathematics Research Center, as well as the university's physics department.

A bomb threat was phoned in to the Madison Police Department, giving five minutes notice of the planned detonation, though previous such calls turned out to be pranks.

[3] The bomb detonated at 3:42 AM on August 24, 1970, killing Robert Fassnacht, a physics post-doctoral researcher who was working late, injuring three others, and causing millions of dollars in damage to the building.

As part of his plea bargain he was sentenced concurrently to seven years each in state and federal prison and was released on parole in 1980 on the condition that he participate in a community rehabilitation program.