Kelvin Cochran, the Atlanta fire chief dismissed because he wrote a book including traditional Christian views of homosexuality, is considering mounting a legal challenge against the city.

He is being represented by religious rights group Alliance Defending Freedom (ADF), which has taken on other high-profile cases.

The group said yesterday it was representing Cochran and that he was wrongfully fired and had not been found to have engaged in discrimination.

"The city nonetheless fired him for nothing other than his Christian faith," the group said. "ADF and Chief Cochran are currently assessing the legal options available to vindicate his right to free speech."

Kelvin Cochran self-published a 162-page book last year entitled Who Told You That You Are Naked?, aimed at helping men overcome feelings of guilt over past sins. It defines 'uncleanness' as the "opposite of purity; including sodomy, homosexuality, lesbianism, pederasty, bestiality, and all other forms of sexual perversion". It discusses homosexuality in half a page.

Cochran is a deacon, Sunday School teacher and Bible study leader at Atlanta's Elizabeth Baptist Church. He was suspended a month ago and ordered to undergo 'sensitivity training' when the book was brought to the attention of city council member Alex Wan, who is gay.

The sacking comes after investigators said that Cochran had failed to obtain the city's permission to publish the book and had refused to remain silent about the matter during the investigation, contrary to instructions not to speak to the media. Other finding have not been released. Cochran denied both charges, and said that allegations of discrimination against homosexuals were "completely unfounded". "The investigation shows that there is no evidence. Under no circumstances have I been discriminatory or hateful towards any member of the department in the LGBT community or a member of the LGBT community at large."

However, Mayor Kasim Reed said at a press conference: "Despite my respect for Chief Cochran's service, I believe his actions and decision-making undermine his ability to manage our fire department.

"Every single employee under the fire chief's command deserves the certainty that he or she is a valued member of the team and that fairness and respect guide employment decisions. His actions around the book and his statements during this investigation have eroded my confidence in his ability to convey that message."

He added that a "decision to retain Chief Cochran" could have caused the city to be held liable in potential anti-discrimination lawsuits.

Mike Griffin, public affairs representative for the Georgia Baptist Convention (GBC), told Baptist Press that Cochran's firing was "a religious liberty issue".

"It comes down to his belief," Griffin said. "Would we have this discussion if he had written a book on hunting or fishing? I don't think so."

in a statement on Thursday Cochran accused the city of Atlanta of intolerance.

"This happened to me, but it's really not about me," he said. "It's a warning to every American that freedom of speech and freedom of religion are hanging by a thread, which will snap if we don't fight to preserve these cherished protections."

Additional reporting by Reuters.