"The kind of manipulation that occurred here is really sinister in my estimation," Waukesha County District Attorney Brad Schimel said Wednesday.
The students go to New Berlin Eisenhower High School in New Berlin, which is in Waukesha County about 15 miles west of Milwaukee.
Anthony Stancl, of New Berlin, was charged Wednesday with five counts of child enticement, two counts of second-degree sexual assault of a child, two counts of third-degree sexual assault, possession of child pornography, repeated sexual assault of the same child and making a bomb threat.
Stancl's attorney, Craig Kuhary, said Stancl plans to plead not guilty to the charges and hopes to reach a plea agreement with the district attorney
"It's too early in the case for me to make a statement, other than the fact at some point we are going to go into events that had taken place earlier that might have had some impact on what he did here," he said. He wouldn't go into specifics.
The incidents allegedly happened from spring 2007 through November, when officers questioned Stancl about a bomb threat he allegedly sent to teachers and wrote about on a school's bathroom wall. It resulted in the closing of New Berlin Eisenhower Middle and High School.
According to the criminal complaint, Stancl first contacted the students through the social networking site Facebook, pretending to be a girl named Kayla or Emily.
The boys reported that they were tricked into sending nude photos or videos of themselves, the complaint said.
Thirty-one victims were identified and interviewed and more than half said the girl with whom they thought they were communicating tried to get them to meet with a male friend to let him perform sex acts on them.
They were told that if they didn't, she would send the nude photos or movies to their friends and post them on the Internet, according to the complaint. Stancl allegedly used the excuse to get the victims to perform repeated acts, the complaint said.
Seven boys were identified in the complaint by their initials as either having to allegedly perform sex acts on Stancl or Stancl on them. The complaint said Stancl took photos with his cell phone of the encounters.
Officers found about 300 nude images of juvenile males on his computer, according to the complaint. Prosecutors said the victims were as young as 15.
A preliminary hearing for Stancl has been scheduled for Feb. 26. The maximum penalty if convicted on all charges is nearly 300 years in prison.