Updated

Washington police are investigating five recent high school graduates after seven students were allegedly beaten with pipes and golf clubs in a hazing ritual to gain admission to a school spirit group.

The incident happened Monday night in Kenmore at Forsgren Park, a mother of one of the victims told Q13Fox.

Seven juniors were chosen by seniors to be initiated into the “Naked Vikings,” a non-sanctioned Inglemoor High School football cheering group, another student said, according to KIRO.

"They used PVC pipes, headless golf clubs, and flour and maple syrup. They peed on us and stuff," James Walvatne, a junior at the school, told the station.

Walvatne said he did not try to stop the beatings because he wanted to be a part of the group.

Images of some of the victims showed numerous welts on their backs. One witness said police also found other victims slumped over a log at the park, suffering from hypothermia and bleeding from wounds, KIRO reported.

The club has now been banned from the school. Over the past few years, the Northshore School District has investigated hazing claims linked to the “Naked Vikings,” but were unable to find evidence, Q13Fox reports.

The school is working with the Snohomish County Sheriff’s Department in an investigation into the beatings, Inglemoor High School Principal Vicki Sherwood said in a letter sent to parents Friday.

“Students will no longer be allowed to wear clothing or accessories that represent the Naked Vikings and we will work collaboratively with student leadership to develop a school-sanctioned spirit club that represents our true Inglemoor values and traditions,” she wrote.

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(WARNING: GRAPHIC IMAGES)