PROVO — Leaders of the American Association of University Professors are criticizing Brigham Young University for placing physics professor Steven Jones on paid leave while university administrators conduct a review of his statements and research about the attacks on the World Trade Center.

AAUP general secretary Roger Bowen called BYU's decision "distressing" and said Jones shouldn't have been removed from teaching two classes this semester for statements made outside the classroom.

Jones has published a paper — www.journalof911studies.com — suggesting that evidence shows the World Trade Center towers fell on Sept. 11, 2001, because of pre-set demolition charges, not just because they were struck by airplanes.

"Academic freedom also protects extramural utterances, that is, statements made by faculty outside the classroom when they speak as citizens," Bowen told the Deseret Morning News. "It's very clear there never should be official retribution for faculty who exercise their rights as citizens, with the very careful disclaimer they are not speaking on behalf of the university."

What Jones said in the classroom and how careful he was about disclaimers are subjects of the university review, BYU spokeswoman Carri Jenkins said.

"The university has not come to a conclusion," she said. "This is why we're conducting a review. Professor Jones is still on campus, and he will be a part of this review."

Jenkins said some had expressed concerns to the university about what Jones was saying in classes.

"We do believe professors must speak responsibly," Jenkins said. "Professors need to clarify when they are speaking for themselves on personal concerns. That is a point that professional organizations continue to make."

The AAUP and BYU have a long, adversarial history over questions of academic freedom at the school. The AAUP placed BYU on its list of censured schools in 1998 after the university declined to grant continuing status, its form of tenure, to professor Gail Houston. The group said infringements on academic freedom were "distressingly common" and that the climate for academic freedom was "distressingly poor."

Each year since, the AAUP has invited BYU back to the table. Each year, BYU has declined, citing its vigorous response to the AAUP in 1998.

"Our policies have not changed," Jenkins said. "Since that time our departments, colleges and the university have had accreditations reaffirmed. We have continued to put our effort into becoming a superb university, particularly concentrating on undergraduate education."