Sarah L. Tolzien, 24, a teacher from Arlington Heights, was charged for allegedly having sex with a 16-year-old male student in November, 2008, authorities said. She was released on March 15, 2009, on $10,000 bond.
Tolzien, who coached the cross-country team, allegedly had sex with the student on two occasions while driving him home from cross-country practice, said Matteson Police Sgt. Kenneth Arvin.
Police and Cook County prosecutors, who conducted a four-month investigation before announcing the charges, said the sexual activity took place on Nov. 14 and Nov. 17 of last year.
"The relationship began sometime in October, 2008," Arvin said in a news release.
The student's parents reported the alleged sexual activity to police in early December of 2008 after finding sexually-oriented text messages from Tolzien on his cell phone.
Tolzien was hired as a substitute teacher in 2007 but was later made a full-time language arts teacher and then began coaching the cross-country team, police said.
Police said there have been no other complaints about Tolzien from other students or their parents.