A Missouri woman knew her 13-year-old neighbor was depressed and suicidal when she sent cruel Internet messages to the teenager, her former assistant testified. The girl killed herself after being told the world would be better off without her.

Ashley Grills, 20, told jurors Thursday she helped Lori Drew set up a fake MySpace profile of a 16-year-old boy to lure Megan Meier into an online relationship.

Testifying for the prosecution under a grant of immunity, Grills also said she sent the last message from the fictitious "Josh Evans" to Megan in October 2006 on the day the girl hanged herself.

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When she learned of Megan's death, Grills said Drew told her, "`We could have pushed her overboard because she was suicidal and depressed."'

Testimony was to resume Friday in the case against Drew, who 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.

Prosecutors say Drew, 49, her then-13-year-old daughter, Sarah, and Grills created the MySpace alias in September 2006 to befriend Megan to find out if she was spreading rumors about Sarah.

The case is believed to be the nation's first cyberbullying trial. Its results could set a legal precedent for dealing with the issue of online harassment.

Defense attorney Dean Steward told jurors that Drew did not violate the Computer Use and Fraud Act — used in the past to address computer hacking — and reminded them that she was not facing charges dealing with the suicide. Steward has repeatedly asked U.S. District Judge George Wu to exclude testimony about Megan's suicide and twice sought a mistrial.

Grills, who helped Drew with her coupon magazine business, testified that she told Drew they might get in trouble for the scheme, but that Drew replied, "It was fine and people do it all the time."

Grills said Drew thought the MySpace account was a funny idea and was present about half of the time when Grills and Sarah sent messages to Megan.

Grills said she remembered at least one time when Drew sat down and typed messages on the computer. She also testified that Drew wanted to print the conversations between "Josh" and Megan, lure the teen to a mall and reveal who the fake boy really was.

To finally end the hoax, Grills said she devised a scenario in which "Josh" would move away so Megan would lose interest in him. When Megan persisted, the tactics changed.

"We decided to be mean to her so she would leave him alone," Grills said.

She testified that she sent the final message to Megan saying the world would be better off without her. Prosecutors did not ask if Drew was in the room when that message was sent, but Grills said she believed the message contributed to her death.

Grills said that a short time after finding out that Megan committed suicide, Drew and her husband ordered her to close the MySpace account.

The case is being prosecuted in Los Angeles because MySpace computer servers are based in the area.