Updated 6:25 p.m. -- One woman was hospitalized and a suspected gunman is dead after shots were fired Tuesday afternoon inside the Alliance Center at 15th & Wynkoop streets in Denver's LoDo neighborhood.
Denver Health says the woman is in critical condition.
Police spokesman Doug Schepman said it appears she was targeted.
"This was not a random shooting," he said.
The suspect was pronounced dead at the scene with an apparent self-inflicted gunshot wound. Detectives are trying to determine the connection between the two.
Companies and organizations in the building include Conservation Colorado, the Sierra Club, Healthier Colorado, Common Cause, Trout Unlimited, National Resources Defense Council and Streetsblog Denver. The building is between 15th and 16th streets on Wynkoop Street, which is the same block as the Tattered Cover and not far from Union Station.
Sam Lauer with Bike Denver said he was in a conference room in the building when he heard people start screaming.
"And at that point I saw people running toward the door. They mentioned there was a shooter on the second floor, at which point I decided to follow them outside and get out of there," he said.
Roads in the vicinity are closed to traffic and police are asking the public to stay away from the area.
CPR's Nathaniel Minor and Hart Van Denburg contributed to this report.