CPD did not immediately provide any additional information about the person.
Earlier Thursday, Chicago police released images of the man accused of shooting and killing two people at Navy Pier.
Police said a disgruntled employee shot two of his former co-workers at Navy Pier Tuesday afternoon.
He is described to be 6'2'' tall, and weighs about 230 pounds with black hair and brown eyes.
Chicago police said he fled the scene using public transportation.
Anyone with information is asked to call (312) 744-8261 or call 911.
READ ALSO | Disgruntled employee shoots, kills 2 at Navy Pier: Chicago police
The suspect had worked for the Levy company before being let go several weeks ago.
Police said that's how he gained access to the employee-only area, where he shot his former coworkers.
CPD arrived at the pier shortly after the shooting, and locked down the area, but they said the gunman took off immediately after opening fire.
The victims were identified as Lamont Johnson, 51, and Peter Jennings, 47, according to the medical examiner.
Johnson's aunt said he had worked at Navy pier for more than 20 years. The family is devastated by his death, saying he was a caring man who always helped those around him.
"I'll remember him as a caring person, a giving person. He just reached out to help others; he was a good person," Candy Johnson said.
Relatives of the victims say they're hoping for justice.
"He was just a working man; he took care of his children. He took care of his mom for the last years she was around," Johnson said.
In a statement Thursday, a Navy Pier spokesperson said, "Navy Pier expresses immense gratitude to the Chicago Police Department for their swift and coordinated efforts following this tragic incident. We are relieved that the suspect has been taken into police custody and extend our deepest condolences to the loved ones of Lamont Johnson and Peter Jennings, who were treasured members of the Navy Pier community."
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