Tragedy struck Citigroup Center in Chicago Friday, when a 59-year-old man forced a guard at gunpoint to take him to the 38th floor offices of law firm Wood, Phillips, Katz, Clark & Mortimer. Once inside, he chained up and sealed the exit so no-one could leave. Moments later three men had been shot dead, and a woman was injured. The three men all worked at the firm, two were lawyers. The shooter was then taken out by a SWAT team which attended the scene.
According to The New York Times, the gunman, Joe Jackson, told police before he was shot that he felt cheated over a toilet he had invented (the law firm deals in intellectual property and patents. One of those killed was a patent lawyer).
Chicago Police Supt. Philip Cline said that 'there were at least another 25 - 30 people on the floor. I think the Chicago police officers from SWAT saved those people's lives'.
The shooting resulted in the railway station beneath Citigroup Center being locked down. The station was crowded and described as resembling 'a zoo'. People initially feared that they would be there all night, although the station eventually re-opened at around 5pm, less than 2 hours after the shooting started.
Security is said to have now been enhanced at the Center, and staff at the law firm have been given Monday off.