A former teacher in Wisconsin accused of sexually assaulting a 14-year-old student nearly two decades ago has a “dark side,” a prosecutor told jurors this week.

Jason LaVigne, a 46-year-old former teacher at Little Chute High School, was charged in June with repeated sexual assault of the same child after the victim sent an email to a school counselor in 2009 alleging that LaVigne rubbed his erect penis against her several times as she sat in a keyboarding class roughly a decade earlier, according to a criminal complaint obtained by the Appleton Post-Crescent.

The woman claimed the incidents took place when she was a freshman at the school. Outagamie County Assistant District Attorney Patrick Leigl told jurors during his opening statement Tuesday that the district’s superintendent, David Botz, concluded there wasn’t sufficient evidence to suggest LaVigne acted inappropriately and decided not to contact police or child protective services.

State law requires school employees to report suspected child abuse or neglect, but police later determined that Botz would not face charges in connection with the case, which Leigl warned “isn’t going to be pleasant,” according to the newspaper.

The woman’s claims didn’t surface until LaVigne was charged with third-degree sexual assault in early June in a separate incident in Marinette County, leading investigators to take a look at his school personnel file, which contained a report by Botz on the previous allegations.

In that incident, LaVigne is accused of sexually assaulting a 16-year-old girl after taking the teen to a cabin with his family. LaVigne also took the victim on a pontoon boat, where he plied her with alcohol before sexually assaulting her, according to a criminal complaint.

LaVigne allegedly sexually assaulted the teen — who told investigators she believes she drank four vodka lemonades — after pulling the boat into a beachy area while his daughter was asleep. The teen said she told LaVigne to stop but he didn’t listen, WLUK reports.

Leigl told jurors Tuesday that LaVigne has a pattern of being sexually attracted to teenage girls. But his attorney blasted that characterization, calling the allegations he faces regarding the 14-year-old girl “absurd” and “ridiculous,” the newspaper reports.

“It just doesn’t make any sense,” defense attorney Frank Stupak told jurors.

The alleged student victim, meanwhile, declined to return to the high school in 2009 to further detail her allegations. She took the stand Tuesday as the prosecution’s first witness and recalled receiving an apology typed on a computer after being asked by LaVigne to meet her after class.

The message also promised not to touch her again, but the entire experience left her “very shaken” and too scared to relay the accusation to anyone, she testified.

LaVigne, who has taught at the school since 1997, is expected to head to trial in Marinette County next month. The Little Chute School District placed him on administrative leave after charges were filed in that county, WBAY reports.