Excerpts from abc7chicago.com:

At about 2:30 p.m., Chicago firefighters responded to a house in the 6900-block of South Artesian. The fire was burning in the basement. Firefighters were told that a child was missing and they were able to pull him from the house. The 3-year-old boy was not breathing when he was found and transported to Holy Cross Hospital, where he was pronounced dead.

The fire was started by an electrical panel that had an unauthorized modification, according to a fire department tweet. 

Tags: 3-, 3-year-old dies in fire, Chicago Fire Department, fatal fire in Chicago