Now police and prosecutors want to know who bought the alcohol.
John Gorman, a spokesman for Cook County state's attorney Richard A. Devine, said the students — all 17- and 18-year-old seniors — will be charged as adults in the May 4 incident.
Devine announced at a late morning press conference that the students were expected to turn themselves in to a courthouse by 1 p.m. CT.
They were to be photographed, fingerprinted and asked to post bond before being released until their court date of June 11.
The investigation is continuing. Devine said it was focused now on determining who provided alcohol that the students consumed before and during the hazing.
"Those who are responsible for that bear a heavy burden," Devine said. He implored people with information to come forward.
The students are accused of participating in a melee in a Cook County park that was captured on videotape.
Glenbrook North High School senior girls are shown on the tapes beating junior classmates and covering them with mud, paint, feces and garbage in what was originally supposed to be a "powder puff" football game. Five girls ended up in the hospital.
CBS News Correspondent Jim Axelrod reports one girl even used a dead fish to strike another young woman.
The seniors apparently invited the juniors to what they described as a hazing, charging them $35 to $40 and supplying them with jerseys, officials said.
School officials stressed that the game was not sanctioned and occurred off-campus without their knowledge.
"I guess there was some football involved, but then it was pushing, punching, hitting, putting buckets on heads … showering people with debris and, according to one report, human excrement," said Northfield Township District 225 Superintendent Dave Hales. "It was hazing. It was deplorable treatment."
Hales said he was baffled why students participated in the game.
"Why would you pay money to go to something where you know you will be treated inappropriately and humiliated and possibly injured?" he said.
An injured girl who needed stitches told the Chicago Tribune they expected only some form of mild hazing, "a friendly initiation into our senior year."
Misdemeanor battery charges carry a maximum sentence of nearly a year in jail, Gorman said. A sentence could also include probation, supervision and a $2,000 fine.
The school, in the affluent suburb of Northbrook, has suspended 32 students who officials claim took part in the hazing. Although the event was off-campus and not sanctioned by the school, officials have said state and local school codes allow the 10-day suspensions.
Principal Michael Riggle says the school is recommending the students be expelled. Expulsion would bar them from the campus and school activities such as prom and graduation ceremonies, although they would still receive a diploma.
Some students have filed lawsuits to overturn the suspensions. Others are going through the school's appeals process.