CHICAGO—A gunman shot four people, killing three of them, in law offices on one of the top floors of a downtown skyscraper on Friday and took a hostage before he was shot by a police sniper, authorities said.
The shooting shut down a commuter rail station at the base of the 42-story office tower, stranding thousands of commuters as workers fled from the offices above.
The gunman, who was armed with a revolver, a knife and a hammer, entered the law office carrying an envelope as a ruse.
"We feel he did have previous encounters with the individuals in that office," said Police Superintendent Phil Cline, without being more specific about the motive.
Once inside the gunman opened fire, wounding three people fatally. He had taken a hostage and chained a door when a police sniper shot down a long hallway, striking the gunman.
"There were at least another 25 to 30 people on the floor and I think the Chicago police officer -- SWAT -- saved those people's lives," said Cline.
He said the gunman may have shot himself as well, but an autopsy would have to show which was the fatal wound.
Feeds