A man clearing snow off the glass roof of the IDS Center skyscraper's atrium slipped, crashed through the roof, and fell about five or six stories to his death on Wednesday, police said.
The man's identity was not immediately released.
"This is clearly an accident," Sgt. Jesse Garcia said.
The man was clearing snow off the roof of the Crystal Court - which contains a food court and retail shops - shortly before 2 p.m. when he fell through the ceiling.
The 51-story IDS Center overlooks the Crystal Court, which features a 105-foot ceiling-to-floor water fountain and a canopy of glass skylights. The building's Web site says the skylights are 121 feet above ground.
Garcia said police cordoned off the lower part of the Crystal Court and were in the process of clearing the skyways entering into the IDS Center.
"We don't have to make this a public viewing," he said.
A message left Wednesday with the building's manager was not immediately returned.
The IDS Center has been the site of two suicides in the last 11 years. In 2001, a 30-year-old man jumped from the 51st floor, crashed through the Crystal Court, and landed by a fountain near a restaurant. In 1996, a 32-year-old man knocked out a window in the 30th floor of the IDS Center and jumped headfirst to his death.
The IDS tower, a city landmark built in 1972, overlooks the Nicollet Mall, downtown's major shopping area. Scenes from the Crystal Court were featured in the opening segment of the original Mary Tyler Moore show.