MONTREAL - An ex-commando was arrested just 24 hours before the release of his candid memoir about life in Canada's elite Joint Task Force 2, leading his co-author to suggest authorities are trying to discredit the book's claims.

Denis Morisset was preparing to do publicity for his book detailing secret missions in Afghanistan, Peru and even an Ottawa bank, when he was arrested Tuesday and charged with contacting two minors with the intent of committing sexual crimes.

Morisset appeared in court on Wednesday as his French-language book was released in Quebec stores.

The military said the book is a threat to national security while Morisset's publishers called it the only public, first-hand account about the inner workings of the JTF2.

Morisset, who says he was a member of the special forces unit for eight years, was preparing to do publicity for his book "Nous Etions Invincibles'' ("We Were Invincible") when he was arrested.

"The coincidence is strange,'' Morisset's ghostwriter, Claude Coulombe, told The Canadian Press. "Why do this on the eve of the book's publication?''

"Nous Etions Invincibles'' traces Morisset's ambitious beginnings with the JTF2 from its inception in 1993 to his disillusioned transfer in 2001.

Though vague on dates, the book contains startling revelations about the obscure unit's purported activities at home and abroad.

Morisset claims JTF2 was called as backup in a hostage-taking at an Ottawa bank in 1994.

The force's commanders informed them it would be good opportunity to put their training in practise and ordered them to "eliminate'' the hostage-takers.

In Morisset's telling, the commandos entered the building, shot the suspects, then left -- leaving Ottawa police to take care of the hostages.

Jean-Claude Larouche, the book's publisher, says he received a letter Monday from the Department of National Defence warning the book's publication could threaten national security.

A spokesperson for the department echoed the concerns expressed in the letter.

"Mr. Morisset's book is an unauthorized account of the Joint Task Force 2,'' said Lt. Isabelle Riche.

"Such publications have the potential to endanger the safety of JTF2 members and their families. They can also jeopardize the effectiveness of operations by disclosing sensitive and classified information.

"In order to mitigate those risks, all members of JTF2 sign a non-disclosure agreement upon leaving the unit.''

In his book, Morisset says the unit helped take out more than a dozen Shining Path guerrillas after they took Canadian ambassador Anthony Vincent and a host of other dignitaries hostage on Dec. 17, 1996.

All the militants and one hostage died in the raid 126 days after the standoff began.

Morisset relates a mission in Afghanistan, conducted sometime prior to 2001, that he says was ordered by CSIS without government approval.

The mission was aimed at gathering information about a cease-fire agreement along Tajikistan border, but ended when the soldiers were caught in a firefight between the two sides.

Morisset says he was shot in the knee during the incident.

Morisset has faced legal trouble before. In 2003, not long after he left the military, he pleaded guilty to similar sex charges and served a 14-month prison sentence.

He claims in his book that at the time he was conducting an investigation for CSIS into government employees using the Internet for pornography.

Morisset says he was ordered to admit the crimes, but maintains today he did nothing wrong.

Quebec police wouldn't comment on their investigation, but Coulombe raised the possibility that it was a rush job.

"One of the accusations says he was on the Internet at 6:35 (Tuesday) morning,'' said Coulombe. "But at that time he was giving a radio interview... he can't be at two places at once.''

Morisset's publisher was taken aback by his author's sudden arrest Tuesday.

"I am surprised, disappointed and pained,'' said Larouche, the head of Les Editions JCL.

Coulombe insists there are few details in the book that were not already available in previous books about the unit.

One of its most damning allegations may be that six JTF2 members have committed suicide over the years.

Coulombe, who has known Morisset since 1993, says the book was a way for the one-time commando to deal with his own severe case of post-traumatic stress disorder.

"It's not a book of revenge,'' he said. "It really was to lift a weight off his shoulders.

Morisset's friend and co-writer is worried about how he will cope in the meantime.

"He told me (from jail) that `six members have killed themselves so far and they want a seventh one, so they're going it,''' Coulombe said.

"I am really worried about what will happen next.''