The five-foot long cougar was killed in the 3400-block of North Hoyne in the Roscoe Village neighborhood.
By mid-afternoon Monday, dozens of residents had seen the mountain lion running and jumping through Roscoe Village.
"He ran across the street, skipped the fence," said Frank Hirschmann, resident.
"It ran across the street and bounced over the fence," said Shannon Johnston, resident.
Police finally killed the cougar in an alley around 5:30 p.m. They had cornered it sometime earlier but fired several shots and missed.
"Initially the animal charged the officers. Shots were fired at the animal. The animal ran into a yard," said Cmdr. John Kenny, Chicago Police Dept.
During the second confrontation, officers put the big cat down with another barrage of bullets.
"How long has thing been in the neighborhood? I mean, this is Roscoe Village, this is the city of Chicago," said Ted Wallace, resident.
An Animal Care and Control worker said it was unlikely it was the same mountain lion sighted on the North Shore earlier this month and did not know if it was wild or an escaped pet.
"It doesn't look like a thin cat. It looks like it has good flesh on it. It was eating well wherever it was," said Mark Rosenthal, Chicago Animal Care & Control.
One witness says the cougar leapt over a 6-foot tall wrought-iron fence. Authorities say the animal's body will be checked for any markings, chips or tags that would show if it is owned by anyone. Authorities in suburban Wilmette say they received several calls on Sunday reporting alleged cougar sightings. Police searched, but did not locate the animal. Confirmed cougar sightings are rare in Illinois.Meanwhile, there was other concern in the neighborhood about all the shots police fired during the chase.
"I would say there were probably three sets of shots, six shots each set," said Johnston.
"It concerns me that this many shots were fired with children present and in close proximity to children," said David Cerda, resident.
Just last year, Chicago had another bizarre wild animal incident - the coyote that wandered into a sandwich shop downtown .
He got in through an open door at the Quizno's at Adams and Wabash. For nearly an hour, the coyote sat in a cooler until it was captured by animal control.
He was taken to a wildlife refuge in northwest suburban Barrington before being released into the wild.
If you have photos or video of the incident please email wls-tv.website@abc.com The Associated Press contributed to this report.