EVANSTON, Ill. (CBS) — A woman may be in serious trouble with the law, after emergency responders from multiple agencies searched the lake off the shore of Evanston for her while she was hiding all the time.

The woman was either scantily clad or completely naked as she walked into the Dempster Street Beach House around 7 a.m. Friday, five and a half hours after the frantic search began for her in the lake, Evanston fire officials said.

“Apparently she hid somewhere while all the activity and search was being conducted,” reported Fire Chief Greg Klaiber.

Police are considering appropriate charges for her, Klaiber said.

Fire Department personnel were summoned to the scene after a swimmer was spotted swimming off the Dempster Street beach around 1:30 a.m. Friday.

Responding police officers spotted the woman swimming off shore at that time, Klaiber said in a dispatch on the incident.

Their calls to her were ignored, he said, and she continued out into the water.

Officers found the woman’s clothing and identification at the beach. She appeared to be a 49-year-old resident of Chicago, Klaiber reported at the time. Her car was located nearby as well.

Not witnessing her return to shore, police summoned Evanston Fire Department personnel. A Mutual Aid Box Alarm System call for divers also was activated.

Helicopters from the U.S. Coast Guard and Chicago Fire Department were brought to the scene, and Evanston’s lifeguard boat also took part in the search.

Sonar was used in the search, which was suspended after two and one-half hours, officials said.

Officials were prepared to launch the department’s special water craft team this morning.

The incident came on the heels of a drowning of a 14-year-old Evanston boy last week near Gillson Park in Wilmette.

The Evanston Review contributed to this report, via the Sun-Times Media Wire.