Tina Meier often sat with her daughter while she was online to ensure nothing fishy was happening.

Lori Drew wanted to find out what kind of nasty rumors were being spread about her daughter.

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Both women — once neighbors and friends — have been described as protective mothers worried about their children.

But as a trial opened Wednesday in a Los Angeles federal courtroom, Drew sat as a defendant while she watched Meier recount from the witness stand how her 13-year-old daughter, Megan, committed suicide after receiving mean-spirited messages from a boy whose identity was later revealed to have been allegedly invented by Drew, one of her employees and her daughter. Testimony is set to resume at 10:45 a.m. PT Thursday.

Drew, 49, is accused of conspiring with her then 13-year-old daughter, Sarah and Drew's then 18-year-old assistant, Ashley Grills, to dream up a fictitious teen on MySpace to find out what was being said about Sarah.

"'As a mother you have to protect your daughter,"' testified Susan Prouty, who advertised with Drew's coupon book business, recalling the reason Drew gave her when the two talked in early 2007 about contacting Megan.

Drew has pleaded not guilty to one count of conspiracy and three counts of accessing computers without authorization. Each count carries a potential sentence of five years in prison.

It's believed to be the nation's first cyber-bullying trial and its results could set a legal precedent for dealing with the issue of online harassment.

Defense attorney Dean Steward told jurors Drew did not violate the Computer Use and Fraud Act — used in the past to address computer hacking — and reminded them she was not facing charges dealing with the suicide.

"This is not a homicide case," Steward said.

While the case is expected to center on the nuts-and-bolts of a social networking site's terms of service, most of the first day's testimony dealt with Megan's suicide.

A composed Tina Meier told jurors her daughter was taking medication for attention deficit disorder and depression and that she struggled with low self-esteem. Concerned with her safety, Meier said she had Megan's father reverse the lock on her daughter's bedroom.

"I was nervous she would do something," said Meier, who added Megan had tried to commit suicide once before.

Meier said Megan was bullied at the Missouri school she attended with Sarah. Megan transferred to a private school months before she killed herself.

Megan was doing well at her new school when she met "Josh Evans" on MySpace in early September 2006 and wanted to be her friend, said Meier, who put restrictions on Megan's computer usage, including having a parent in the room when she was online.

But on the rainy day Megan died in October, Meier says she took her younger daughter to the orthodontist and when she called to see how Megan was doing, her oldest was crying. "Josh" and two other girls were saying mean things about her, Meier said.

When Meier arrived home, Megan showed her what was being said. One of the messages said the world would be better off without her. Meier testified she told her daughter that she wasn't supposed to be online without her being there.

"The last words she said to me were 'You are supposed to be my mom, you are supposed to be on my side,"' Meier said as she tried to hold back tears.

Meier said she later ran later upstairs and found Megan hanging in the closet with a belt around her neck. She died the next day.

In his opening statement, U.S. Attorney Thomas O'Brien disclosed for the first time what Megan wrote after "the world would be better off without her."

"'You are the kind of boy a girl would kill herself over,"' O'Brien said of Megan's message.