A teacher, coach and City Council member in Glenwood City, Wis., has been charged with five felony counts for allegedly having an online sexual relationship with a 15-year-old girl.

Authorities on Thursday interviewed Peter Gaustad at Glenwood City High School, where he is a Social Studies teacher, and escorted him across the street where he was arrested, officials with Wisconsin's Internet Crimes Against Children Task Force said.

Gaustad was charged with two counts of sexual exploitation of a child, one count of exposing a child to harmful material, one count of causing a child to view and listen to sexual activity, and one count of using a computer to facilitate a child sex crime, according to a criminal complaint filed Friday in St. Croix County District Court.

Gaustad, 45, has been placed on administrative leave, according to a letter sent to parents by high school principal Patrick Gretzlock.

Gaustad had taught middle school and high school students in the small district east of Hudson for 19 years. He also was the head varsity softball coach for the high school team and a junior varsity girl's basketball coach, said Superintendent Tim Johnson.

"It's awful," Johnson said. "He was a person that people connected with."

No students in the Glenwood City schools appeared to be victims, according to the joint investigation conducted by the sheriff's office, the Glenwood City Police Department and the Wisconsin Department of Justice. Johnson said it is believed that all activity took place off school grounds.

Authorities in Boone County, Missouri, where the teenage girl lived, notified authorities in St. Croix County after the girl's mother learned about the relationship that her daughter was having with a man through online apps.

Wisconsin investigators determined that Gaustad developed a relationship with the teen over several months, included the sharing of explicit sexual images and videos over apps such as Snapchat and Whisper. Some of the exchanges occurred while he was at his home.

Authorities searched his home and searched his belongings at school before he was arrested.

Gaustad was also chairman of the City Council's public utilities committee, according to the city's website.

Glenwood City is about 50 miles northeast of downtown St. Paul.

Tim Harlow • 612-673-7768