Students at Cascade Middle School were told to leave their backpacks at home Thursday, as the only thing they needed to bring to school was a pen to sign each other’s yearbooks.

But they didn’t realize they wouldn’t be able to take their yearbooks home on the final day of class, after school officials discovered inappropriate material inserted into them by hackers .

“This is definitely a disappointing lesson for the students involved,” said Julianne Repman, communications director for Bend-La Pine Schools. “It’s a sad way to end the school year.”

About 750 Cascade Middle School yearbooks were confiscated from students Thursday after some students hacked into the yearbook design file and put inappropriate material under multiple student and staff photos.

Repman said school officials knew about the hacking three weeks ago, but the yearbooks had already gone to the printer at that point. Repman said the school worked with the printer, Herff Jones, to cover the inappropriate material with stickers, and school officials were told these stickers would not peel off.

Eighth-graders at the school were given the yearbooks Wednesday, and the rest of the school received them Thursday morning.

It was quickly discovered the stickers could be peeled away and that there was even more inappropriate content in the yearbooks than school officials had initially thought.

Students were then asked to return the yearbooks, but told they would be allowed to keep the signature pages. All but about 20 copies of the yearbook were returned.

“We’re so proud of the students because they knew it was the right thing to do to get the yearbooks out of circulation,” said Repman.

In an email sent to parents Thursday, Cascade Middle School Principal Stephanie Bennett said the cost of reprinting the yearbooks would be $10,000.

“We hope to be able to reorder this year’s yearbook — but the cost may be prohibitive,” Bennett said in the letter. “We have some hope that those responsible for this prank will pay restitution to cover the costs of reproduction.”

Bennett also said in the email that parents could get a refund for the yearbook. If the school is able to get the books reprinted, they won’t be ready until the beginning of the 2014-15 school year, the principal said.

The district knows who some of the student hackers are, and an investigation is continuing, Repman said. She could not confirm if all the students attended Cascade.

Stewart Fritchman, the owner of Bellatazza Coffee and father of a Cascade Middle School eighth-grader, was notified about the yearbook incident via Bennett’s email Thursday afternoon. Fritchman also heard from some parents on Facebook that the inappropriate content in the yearbooks was of a derogatory and possibly racist nature.

Repman said she didn’t know the details of the inappropriate material.

“Within minutes of hearing about it, I wanted to put something together,” Fritchman said. “We want to show that there is no tolerance for this in our community.”

Fritchman said he will pledge $1,000 to the school to help reprint the books and will also try to rally other small businesses to pledge their support.

“It’s nice to pay $20 for your own child to have a reprint, but many families in the community might not be able to afford that,” he said. “This is a message we need to send.”

Fritchman said his son was disappointed about having to give the yearbook back but understood the reason for it.

“He knew that what was going on was not cool,” Fritchman said.

— Reporter: 541-383-0354, mkehoe@bendbulletin.com.