CPD responded just before 12:15 a.m. to a fire in the garage of a high-rise building at Ninth Street and Wabash Avenue.
When officers arrived, Chicago fire crews were extinguishing three vehicles.
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Further investigation determined arson was the cause of the blaze, Chicago police said.
No one was in custody later Thursday morning, and police did not immediately provide any information about a possible suspect or suspects.
This is a developing story; check back with ABC7 Chicago for updates.