The search has even shut down roads, driveways and parking lots around an area park.
The five-foot gator, nicknamed "Chance the Snapper," was spotted in the lagoon last Tuesday and sightings have been drawing crowds.
Just landed and found out I gotta alligator— Chance The Rapper Album in July (@chancetherapper) July 10, 2019
"I don't think I have seen a gator in real life, but if I do see one, I intend to Steve Irwin that thing right into the water and bringing it back where it belongs," said Derek Allen.
Chicago Animal Care and Control said it's likely that residents who have been watching from the lagoon banks have been influencing the animal's behavior, possibly making it harder to catch.
"The City of Chicago is taking the necessary steps to safely and humanely capture the alligator, which means keeping the lagoon and surrounding areas as calm and quiet as possible," said Kelley Gandurski, Executive Director of Chicago Animal Care and Control. "It is likely that residents who have been watching from the lagoon banks and paths in the park have been influencing the animal's behavior. We are taking these steps to in an attempt to create an environment that lends to the animal's safe capture so we can quickly re-open the entire park to activity."
The city has hired expert Frank Robb, who owns Crocodilian Specialist Services in St. Augustine Florida, to catch the gator after authorities say he was recommended by local experts there. He arrived in Chicago Sunday and has been assessing the situation.
The boathouse parking lot, all pedestrian paths within the park and bounded by Humboldt Park Drive, Division Street, California Avenue and North Avenue are closed until further notice. All access to North Luis Munoz Marin Drive east of North Humboldt Park Drive is also closed.
Meanwhile, west half of the park remains open.
It is a misdemeanor to have a pet alligator in the state of Illinois, and it is also illegal to release a pet into a public park.
A Chicago police investigation into who released the alligator is ongoing.