A professor who has questioned whether planes destroyed the World Trade Center in New York on Sept. 11 five years ago has been placed on paid leave by Brigham Young University while the LDS Church-owned school investigates his statements.

Steven Jones, who has taught at BYU since 1985, has written that the towers fell because explosives were placed inside the buildings. He is co-chairman of a group called Scholars for 9/11 Truth.

In a formal statement, BYU said it was "concerned about the increasingly speculative and accusatory nature of these statements by Dr. Jones."

"BYU remains concerned that Dr. Jones' work on this topic has not been published in appropriate scientific venues," the statement said.

BYU, a private university operated by The Church of Jesus Christ of Latter-day Saints, also is concerned about its reputation, spokeswoman Carri Jenkins said. "It is a concern when faculty bring the university name into their own personal matters of concern," she said.

"With any faculty member, my advice to them is to wait until their work is published before they discuss it with the media," Jenkins said

Jones was teaching two introductory physics courses this semester. His classes have been handed off to other professors, Jenkins said, and the review is expected to take at least until the semester ends.

In an e-mail to The Associated Press, Jones declined to comment on Friday.

The physicist published his views two weeks ago in the book "9/11 and American Empire: Intellectuals Speak Out." He has been widely quoted by The Associated Press and other national media.

His work focuses on the relatively narrow question of whether molten metal present at the World Trade Center site after the attacks is evidence that a high-temperature incendiary called thermite, which can be used to weld or cut metal, was involved in the towers' destruction.

He concludes thermite was present, throwing the government's entire explanation into question and suggesting someone might have used explosives to bring down the towers.

"I have not run into many who have read my paper and said it's just all hogwash," Jones recently told the AP.

While Jones is on leave, BYU said it will review his involvement among people who believe there was a government conspiracy to the attacks.

The review will be conducted at three levels: by the university administration, the College of Physical and Mathematical Sciences and the Physics Department.

Critics have accused Jones of venturing outside his area of expertise to draw conclusions. Jenkins said that prospect would be examined during the review. "That is the expectation of faculty, that their research, their work be in the area of that person's academic scholarship."

At the University of Utah, Physics Department Chairman Pierre Sokolsky said destruction of the towers typically would be a field within the expertise of engineers.

"This is not physics," Sokolsky said, referring to Jones's field. "I don't want to comment on BYU's actions. But if someone in my department was doing this, I would find it disconnected from the academic activities of the department."

Daily Herald reporter Anna Chang-yen contributed to this story.