Updated

A Purdue University professor has filed a freedom of speech suit against his school and five co-workers after getting in hot water for inflammatory statements about Muslims on his Facebook page.

Tenured political science professor Maurice Eisenstein was cleared by a university investigation into his Facebook comments, which included a reference to "the idiot Mohammad [sic}, may his name be cursed." But Eisenstein claims the investigation nonetheless damaged his reputation and disputes a finding that he retaliated against other faculty members.

“I was trying to be challenging as a professor, and do what I was trained to do,” Eistenstein, who joined the school's faculty in 1993, told FoxNews.com.

The flap unfolded late last year, when Eisenstein posted a photo of the aftermath of a massacre of Nigerian Christians, purportedly carried out by African Muslims, on his Facebook page.

"Where are the ‘moderate' Muslims' reaction to this? Oh, I forgot they are still looking at the earth as flat ...,” Eisenstein wrote above the post.

More On This...

Other members of the faculty, as well as members of the Muslim Student Association, learned of the comments and went to school officials. Eisenstein maintained that the post was on his personal page and in no way reflected on the school. History professor Miriam Joyce, who later filed a harassment complaint against Eisenstein, told FoxNews.com the comments could alienate students.

“We have Saudi students," Joyce said. "We have other Muslim students. This is wrong. It creates an unpleasant and  unwelcoming atmosphere. “I’m concerned that Muslim students and their parents will get the wrong idea about my school.”

The Muslim Student Association could not be reached for comment.

The school's investigation, led by Chancelor Thomas Keon, cleared Eisenstein in January of violating the college’s free-speech and anti-harassment rules. However, he received a written reprimand for allegedly retaliating against Joyce, as well as a second professor, Saul Lerner.

Eisenstein denied retaliating or harassing his colleagues, but acknowledged a bitter e-mail exchange with Lerner and denies making a callous reference to Joyce’s son, a former hedge fund manager who committed suicide.

Eisenstein said his freedom-of-speech suit is the result of the university’s investigation into his comments about Muslims - even though the probe ostensibly cleared him.

[pullquote]

“When you investigate free speech, you chill free speech,” Eisenstein said. “How am I supposed to do my job without free speech. I've changed. Every time I go into a classroom, I look around and wonder who will complain about what I say.”

Eisenstein enlisted the Foundation for Individual Rights in Education (FIRE) in bringing his suit against the Big Ten school.

"This is not the first time and it won't be the last time we will see a university punish a student or professor for constitutionally protected speech on Facebook," said FIRE President Greg Lukianoff. "Professors at public universities should not have to go to court to defend their free speech rights."

Joyce said freedom of speech shouldn't permit a professor at a public school to gratuitously denigrate the beliefs of others, including students at the school.

“I'm all for free speech. I want it for me and I want it for everyone else, but there’s got to be some judgment used," Joyce said. "You don’t cry fire if there isn’t a fire and then say it was protected by free speech.

“I’m a [history] teacher," she added. "I’d rather be dealing with Bahrain than Eisenstein, anyway.”