Marion Horton, 28, of the 400 block of West Division Street, had attacked the off-duty officer, who works security for the building, a seven-story public housing high-rise at 1815 W. Monroe St., and another security guard, said Pat Camden, Fraternal Order of Police spokesman.
The guard from a private security company found a man sleeping in the building's lobby about 6:30 a.m. as she was making her rounds. She told the man to leave, but when the man got to the building's parking lot, he urinated on a parked truck, authorities said.
An off-duty Chicago Police officer, who was working security at the front desk, went out to talk to the man. The officer told the man to move along and identified himself as a police officer, to which the man said, "'Why, what are you gonna do about it? ...Kill me?'" Camden said.
The two continued to argue, and the officer tried to put the man under arrest. The man became combative, and pushed the officer to the ground, authorities said.
The security guard rushed outside to help, and the man attacked her, "literally pull[ed] about 18 braids out of her hair," Camden said.
"It's a vicious fight that's taking place," Camden said.
The off-duty officer feared the man would get the security guard's gun, so he drew his own weapon and ordered the man to put his hands in the air. The man, who Camden described as a "good-sized guy," 6-feet tall and 180 to 200 pounds, lunged at the officer.
The officer, fearing for his life, fired his gun. The man was hit and taken to Stroger Hospital, where he was later pronounced dead, police said.
The off-duty officer and private security guard were both bruised in the attack, Camden said.
Earlier Saturday, police shot a man in his leg in Woodlawn.