(CHICAGO) — Chicago officials have closed a portion of the park where a wayward alligator has been lurking in hopes of catching it. The noise from the onlookers gathering near the Humboldt Park Lagoon may be causing the gator, nicknamed “Chance the Snapper,” to remain underwater, Kelley Gandurski, executive director of Chicago Animal Care and Control, said in a statement on Sunday.Animal control officials are hoping that “keeping the lagoon and surrounding areas as calm and quiet as possible” will help them humanely capture the gator,” Gandurski said.”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,” she said. “We are taking these steps 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.”Chance the Snapper, a 4 to 5-foot indigenous American alligator, was first spotted in the lagoon on July 9. The gator is believed to have been a pet that someone dropped off at the lagoon, Jenny Schlueter, a spokeswoman for Chicago Animal Care and Control, told ABC News last week.The City of Chicago has brought in expert Frank Robb, who owns Crocodilian Specialist Services in St. Augustine, Florida, to assist in the capture. Robb arrived in Chicago on Sunday and has assessed the park and lagoon, according to the CACC. The closure of parts of the park began Sunday night, and will continue until further notice.Just 20 alligators have been seen in Chicago since 1998, Schlueter said. It is believed that Chance is the first gator to surface in the Humboldt Park lagoon.Copyright © 2019, ABC Radio. All rights reserved.