KNIGHTSTOWN, Ind. — Two students are suing to return to school after they were expelled for making a movie in which evil teddy bears attack a teacher.

The teenagers were among four students expelled from Knightstown High School over the movie, titled "The Teddy Bear Master." Two of the boys are asking a federal judge in Indianapolis to order the students reinstated, arguing that school officials overreacted to a film parody and violated their First Amendment rights.

But Knightstown Principal Jim Diagostino and Superintendent David McGuire don't see the humor, and note that the teacher who is threatened in the movie has the same last name as a real teacher in the district.

"That's crazy to think that's a threat to anyone," said Linda Imel, 42, whose 15-year-old son, Isaac, and his friend Cody Overbay, 16, have filed the lawsuit in U.S. District Court.

"We have adults, supposedly — and educators at that — who have failed terribly. They're willing to throw four good kids away," said Imel, whose son has missed more than a month of school.

But the Charles A. Beard Memorial School Board last week upheld the suspensions of Imel, Overbay and a third student who had appealed to return to school. The other boys who were expelled have not taken legal action.

Indiana law allows expulsion for activity unconnected with school if the activity is unlawful and interferes with school operations. The Henry County prosecutor's office reviewed the movie but declined to press charges.

The boys, who are sophomores, worked on the teddy bear movie from fall 2005 through summer 2006. In the movie, the "teddy bear master" orders stuffed animals to kill a teacher who had embarrassed him, but students battle the toy beasts, according to documents filed in court.

"It's a 14- or 15-year-old boy's idea of humor," said Jackie Suess, an attorney for the ACLU of Indiana, which is representing one of the students.

In a letter to school board members, the district superintendent said teacher Daniel Clevenger, who teaches seventh grade at Knightstown Intermediate School, felt threatened by the movie.

Indianapolis attorney Robert Kelso, who represents the school district, wrote in a document filed in court that the movie "contained vulgar and offensive language, threatened and intimidated a teacher."