Liza Leon is starting to hate computers.

Someone is using the Internet to tease and humiliate her 16-year-old daughter, and whoever is behind the cruel open attacks is also hiding anonymously somewhere in cyberspace.

"They put up a phony Web site for her on MySpace," said Ms. Leon of McCandless. "I think it's people who know her, because some of it is true and some of it is making fun of her."

She said she recently reported the bogus Web site to administrators at North Allegheny High School, which her daughter attends, but they advised her to contact the police. So far, she said, police haven't been much help either in finding the culprits.

Bullies of yesteryear spread ugly rumors and abused their peers in schoolyards, cafeterias and bus stops. Now some of them are using high technology to inflict pain and misery through cell phones and computers even when their victim is safe at home.

Scandalous gossip and embarrassing photographs posted online can reach a far wider audience than was ever possible before the computer age.

Cyber bullying has become a growing concern in schools across the country as more students gain access to the Internet and other mobile communication devices that can be used as instruments for harassment and threats.

While many school districts have adopted new rules in their policies to address Internet conduct, administrators must weigh how far they can go in controlling student online conduct while at the same time respecting First Amendment rights.

Educators are sometimes torn over whether to take action for speech that takes place in cyberspace while children are at home.

"That is the province of parents, not school administrators," said Witold Walczak, legal director for the American Civil Liberties Union of Pennsylvania. "They can't play substitute parents when students are at home.

"For students, even though the speech may be protected there's a big difference between whispering on a playground and posting on the Internet. They need to understand you can cause real pain to people on the Internet. The Internet just amplifies the speech, so the consequences are far greater."

Internet hostility can often result in conflicts that spill onto the school campus. But public school administrators are limited in how they can punish a bully for harassing a classmate on the Internet -- unless it happens on a school computer.

"We've had a handful of incidents where kids have made threats to other students [using a school computer] and those kids were dealt with promptly," said Janet Yuhasz, coordinator of student wellness for Pittsburgh Public Schools.

The Pittsburgh school district amended its code of student conduct in June 2003 to include rules regarding computer conduct. The rules do not apply, however, to off-campus computer mischief.

Private schools have more leeway to impose off-campus rules.

"Our basic premise is if it has a negative impact on the school environment then it's worthy of intervention," said Dr. Robert Paserba, superintendent of schools for the Diocese of Pittsburgh.

Pittsburgh Catholic schools teaches an anti-bullying curriculum and has a policy that forbids making threats on the Internet to other students, teachers or administrators. That includes any improper Internet use on and off-campus, Dr. Paserba said.

"Sometimes if something is in bad taste, we've asked that it be removed from the Internet and persons have been cooperative with that," Dr. Paserba said. "We've not found anything so far that rose to the level of police involvement."

Police did, however, charge a 14-year-old Swissvale boy in May with using the Internet to bad-mouth a fellow middle school pupil.

The computer at Sharon Asturi's house is in plain view located in the den.

Ms. Asturi, of Shaler, said she frequently checks to see what her 12-year-old daughter and her friends are typing back and forth to each other on AOL instant messenger.

"It's usually typical little girl conversations, nothing to worry about," she said.

One day recently, her daughter and her friend's screen names popped up on AOL messenger and neither of them were online at the time. The imposter was using profanity and obscene references.

The very next day, it happened again and it's still continuing even though she and her daughter contacted AOL and the local police department's Internet crime division.

"It really scares [us] because the person knows where she's been that day and what she was wearing," Ms. Asturi said. "It freaks her out.

"I don't even know where to go from here. It's mind boggling. They can't figure out who hacked in."

One of the more popular Web sites for teens is a social network called MySpace. It allows young people to post photos and details about themselves.

But it can also be used for large-scale harassment. Internet bullies will sometimes create phony Web sites on MySpace and publicly subject their victims to cruel or embarrassing rumors, threats, harassment and in some extreme cases, stalking.

A quick scan of MySpace profiles clearly shows four-letter words and provocative pictures. Many schools have blocked MySpace so students can't access it from school computers.

At least one private school district, the Diocese of Paterson, N.J., made headlines for telling students they will be suspended for using the site even off campus.

"It was kind of the shot heard around the world," said Marianna Thompson, director of communications for the diocese.

Experts and news reports worldwide tell disturbing tales of students harassed via the computer to the point that they've left school or become severely depressed.

A teenager in New Zealand recently committed suicide after being inundated with dozens of harassing and insulting text messages.

Some school districts have moved to limit the use of cell phones during school hours.

At North Allegheny and West Allegheny school districts, cellular phones with photo capabilities are prohibited on campus.

"Technically, they could take photos of student work and pass it on. Or in the boys or girls locker room, and pass it on," said Bill Englert, assistant to the superintendent at West Allegheny School District. "In our judgement it's one of those things better left at home or in the backpack."

John Hoover is chair of the Special Education Department at Minnesota's St. Cloud State University. He has published dozens of papers and three books on the topic of bullying.

He said cyber bullying is similar to other types of bullying, except it takes place online and through text messages sent to cell phones.

"This creates a distance that allows people to communicate pernicious content more safely and anonymously," Dr. Hoover said. "The Internet is here to stay and is the new battleground for bullies and their victims."

He said his research shows students learn more when they feel physically and psychologically safe. He said other studies also have shown that stress is bad for learning. And bullying is bad for bullies.

"There's a host of evidence from different studies that show bullies end up with miserable adult lives," Dr. Hoover said. "In the short-term, they hold power over their classmates. But in the long-term, they're more likely to drop out, go to jail, have spousal abuse and difficulty with employment.

"Bullies have difficulty with non-violent problem-solving. Bullies don't play well. They don't negotiate. They don't learn to get what they need by forming good habits. Youngsters who bully others miss out on those skills."