Lucas was pronounced dead at the scene, Carson told reporters.
Carson said the gunman was 30 years old and a part-time janitor at the facility, KTVI reported. He said the man had been sent home for disciplinary reasons and spoke briefly with Lucas before shooting her, the television station reported.
There were about 150 people, including many children, in the building when the shooting occurred, the Post-Dispatch reported.
After police were alerted, an officer ran into the community center, and the gunman fired at him several times, breaking the glass in a set of glass doors, the newspaper reported. The officer returned fire and injured the gunman, according to the Post-Dispatch.
The officer was not injured, KMOV reported.
“I believe the action of our police officer was quite heroic. He immediately went inside the community center and confronted the gunman,” Carson told the television station.
The community center has been closed until further notice, officials from the Maryland Heights Police Department tweeted Tuesday.