A group of approximately 40 to 50 Irvington High School seniors vandalized the Fremont campus and spray-painted a swastika in its courtyard pavement Sunday night, according to school Principal Sarah Barrious.

In an interview Tuesday, Barrious said she was “disappointed, embarrassed, frustrated” by what she described as a senior prank gone too far. She said she did not see the swastika while walking the school grounds Monday, but was told of it by a staff member later.

“This is highly offensive, inexcusable, and there’s nothing that you can say to defend what is essentially hate speech,” Fremont Unified School District Superintendent Jim Morris said Tuesday. “There is no excuse for it.”

Some comments on social media postings about the incident, which was reported by the school’s newspaper, The Irvington Voice, expressed outrage over the painting of a hate symbol as part of senior pranks, which typically are lighthearted expressions of celebration at the end of the school year by soon-to-be graduates.

The students also jammed clay into the keyholes of various classroom and office doors so teachers couldn’t get inside, Barrious said. The Irvington Voice Facebook page posted pictures of pipes and assorted junk thrown into an-already drained swimming pool, with profanities written on the pool’s sidewall.

Barrious said when she first saw some chalk drawings on campus Monday, such as those with positive messages of appreciation for staff and faculty, and the plastic wrap applied to parts of school property, she initially thought of senior prank shenanigans.

But her frustration grew as she walked around campus and found chalk drawings on buildings with human “anatomy” and obscenities prominently displayed. Oil had been spread through some of the hallway floors, causing a safety issue.

Barrious said she called the senior class to an assembly and, standing among a collection of brooms, trash cans and other cleaning supplies, told the roughly 450 students they would be cleaning up the damage that morning, which was the last day of classes for seniors.

In a video on The Irvington Voice Facebook page, Barrious told the students “it’s not a senior prank, it’s vandalism.”

“The images and the words that are on the walls of Irvington High School are not something I want in the media,” Barrious told the students. “It does not reflect well on me, or you, or this community. We have to clean it up.”

The Irvington Voice said students used their school ID cards, coins and fingernails to chip and scrape the painted swastika off the courtyard pavement.

They used rags, cleaning products and brooms to remove other drawings and powder that had been laid down to absorb the oil.

In February, two 15-year-old Fremont students admitted to spray painting a swastika among other graffiti on nearby Horner Junior High School property.

Morris said the swastika drawn at Irvington was particularly offensive because Fremont “has a great deal of appreciation for being a multicultural community.”

“It doesn’t represent who we are and who we want our students to be,” he added.

Barrious said that through questioning of some students and some information given to her staff, she has found who is at least partly responsible for some of the pranks, though there are no leads on who painted the swastika. No criminal charges will be pursued, she added.

The Irvington Voice said some students had their phones searched by staff, but Barrious denied that claim.

She said those deemed responsible will still be allowed to walk across the stage at the school’s graduation ceremony Friday morning, but likely will have their diplomas withheld until they return to the school to do additional cleanup next week.

Barrious said in a Tuesday afternoon email to the school community, including parents and guardians, that the school does not tolerate hate speech and that “we will continue to look for opportunities to educate our community in order to build multi-cultural appreciation and to ward off hate.”

Irvington High senior Samiha Uddin posted a note on Facebook about the incident that was shared by The Irvington Voice.

“I used to boast about Irvington for being one of the most accepting and tolerating high school communities in our country…but today was eye opening,” she wrote. “I am still in shock that I will forever remember my last day of high school as furiously having to scrub off a swastika on the courtyard floor.”