Northbrook, Ill. ? Authorities investigating a videotaped hazing in which high school girls were pummeled and showered with feces, paint and garbage are trying to determine whether parents supplied beer and some of the filth.

The melee occurred Sunday during a football game between high school girls in a park in this well-to-do Chicago suburb. Seniors had invited juniors for what was described as an initiation into their senior year.

Videotaped by students and shown repeatedly on national television, the hazing involved as many as 100 teenagers from Glenbrook North High. Five girls were hospitalized, including one who broke an ankle and another who suffered a cut that required 10 stitches in her head.

Cook County Forest Preserve District Police said Thursday that they probably would file criminal charges. Spokesman Steve Mayberry said he did not know the specific charges or how many people would be charged.

Northbrook Deputy Chief Michael Green said that police were investigating whether parents provided alcohol. According to school board member Tom Shaer, two parents might have supplied a keg of beer.

Police were also investigating whether a parent helped gather some of the feces, Shaer said.