COSTA MESA, Calif. — A middle school student faces expulsion for allegedly posting graphic threats against a classmate on the popular MySpace.com Web site, and 20 of his classmates were suspended for viewing the posting, school officials said.

Police are investigating the boy’s comments about his classmate at TeWinkle Middle School as a possible hate crime, and the district is trying to expel him.

According to three parents of the suspended students, the invitation to join the boy’s MySpace group gave no indication of the alleged threat. They said the MySpace social group name’s was “I hate (girl’s name)” and included an expletive and an anti-Semitic reference.

A later message to group members directed them to a nondescript folder, which included a posting that allegedly asked: “Who here in the (group name) wants to take a shotgun and blast her in the head over a thousand times?”

Because the creator of a posting can change its content at any time, it’s unclear how much the students saw.

“With what the students can get into using the technology we are all concerned about it,” Bob Metz, the district assistant superintendent of secondary education, said Wednesday.

Metz said the students’ suspensions in mid-Febuary were appropriate because the incident involved student safety. Some parents however questioned whether the school overstepped its bounds by disciplining students for actions that occurred on personal computers, at home and after school hours.