CHICAGO (CBS) — Three students were expelled from a school in northwest Indiana, for comments they made on Facebook, about which classmates they would like to kill.

Officials at Griffith Middle School said the comments violated policies against bullying and harassment.

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But the American Civil Liberties Union said the 8th graders were clearly just joking around. Now the school is being sued.

CBS 2’s Pamela Jones spoke with an angry mother in Griffith, Ind.

The accused girls said the comments were simply jokes, taken out of context by another student, who reported them to school officials.

One girl started by calling herself ugly, and that’s where the ugly speech began.

“Another girl said, ‘I want to kill all the ugly people,’ ” expelled student Kennedy Fortier said.

Kennedy said no one was serious about that, but it was part of a Facebook conversation that got her kicked out of school.

She and two other 8th graders were expelled after a Facebook conversation in January, in which they discussed which classmates they would kill.

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The students said they used joking terms like “lol” – or laughing out loud – to indicate they didn’t mean what they were saying.

But a girl who was a target of the comments said she takes it all very seriously.

Kennedy’s mother said she didn’t approve of what the girls wrote on Facebook.

“I wasn’t happy. None of us moms were happy with the conversation that the girls were having,” Tabitha Fortier said.

But she said kids at the school post violent comments all the time, but the rules aren’t enforced fairly.

The girls and their parents have filed a lawsuit against the school.

According to the lawsuit, the school said “each girl’s behavior violated a portion of the school’s student handbook concerning bullying, harassment and intimidation.”

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Tabitha Fortier said she was disappointed with what her daughter posted on Facebook, but she said the school should enforce its rules evenly.