EDGERTON, Wis. -- Two Edgerton High School students who district officials said might have been indirectly connected to threats against a school official have been released after being taken into custody Thursday night.

WISC-TV and Channel 3000 are not releasing the identities of the Edgerton High School students because no charges have been filed.

An extra police cruiser is patrolling Edgerton High School to make sure that some threats aren't fulfilled.

Earlier this week, an Edgerton junior wore a T-shirt that featured the band Insane Clown Posse, and school officials sent the student home.

Superintendent Norm Fjelstad describes the band Insane Clown Posse as dangerous gangster music.

"We don't normally legislate T-shirts, but if they're a disruption or if they represent something that is totally inappropriate for our school, the Supreme Court has ruled that the schools have the right to determine a dress code," Fjelstad said.

A peaceful protest by a group of students ensued. And the superintendent received some disturbing messages.

"The e-mails were from ICP juggalos who were going to fly here from New York and be here on Friday, and they would take care of people like me," he said.

The e-mail said the Insane Clown Posse fans, known as juggalos, would show Fjelstad how they deal with an "idiot who looks like and acts like Hitler," adding that the superintendent had "24 hours to change the decision to allow ICP T-shirts, or they would know how to deal with him."

"They just said they would come here; they knew how to take care of people like me; they know me; they know what I look like; they use a lot of vulgarity as they were describing me, and they know I have a family," Fjelstad said.

As a precaution, police are patrolling the campus, and the superintendent is not answering his home phone, WISC-TV reported.

Police released the students Friday afternoon after the district attorney declined to file charges.

An internal district investigation is under way, including a teacher's claim that the two students arrested Thursday made comments in class about shooting everyone at the school except their few friends.