Police hunted for the driver, Nathan Hanna, who apparently fled in his pickup truck.
Employees scrambled under desks or hid in the darkroom after the gunman, apparently aimed for circulation manager Anthony Gillespie, 47, killing him with two shotgun blasts, said Editor Ken Fazzari, who called 911 from under a desk.
Hanna didn't say anything before he started shooting, Fazzari said.
"This is just a total shock and I'm still shaking, have been all day," Fazzari said.
Police Officer John Weist said Hanna had been fired by the newspaper. But Fazzari said to his knowledge, Hanna was still an employee.
Workers in buildings nearby were told to lock themselves in after the attack, and SWAT units surrounded the newspaper offices for four hours, until police determined no hostages were taken.
Officers escorted 14 people out of the building, while others made it out on their own soon after the shooting. Some were taken to a hospital to be evaluated physically and emotionally.
Lex Walsh, whose barber shop is about 100 feet from the building, said the paper's receptionist escaped and ran to his barber shop, extremely distraught and saying others were trapped in the building.
The newspaper is on Michigan's Upper Peninsula, about 350 miles north of Detroit on the Canadian border. It has a circulation of about 7,300.
The paper ordinarily publishes every day but Saturday. Fazzari said the paper wasn't published Thursday and probably won't come out again before Monday.
Written by John Flesher