A Quebec-based soldier says his tour of duty in Afghanistan may be in jeopardy after he was roughed up by Fredericton police officers outside a downtown night club.

Luc Begin, who was in Fredericton celebrating his engagement, has filed a complaint over the incident with the local police and the New Brunswick Police Commission, alleging that he was assaulted.

Begin, normally based at CFB Valcartier in Quebec, told CBC News in an interview on Thursday that he is supposed to go to Afghanistan in October 2010. But the infantry private said he suffered a broken vertebra in his back during the altercation and that could cost him his tour of duty.

"I feel bad because [going to Afghanistan] is part of my job," he said. "Serving my country just like those police — it's part of their job to protect people, not to beat them up."

Witnesses, including one with video footage, support Begin's story.

Just before 1 a.m. on Saturday, Charles LeBlanc, a local blogger, was walking in Fredericton's downtown bar district when he saw several police officers with Begin in front of Sweetwaters.

LeBlanc captured part of the incident with his video camera.

"He didn't resist. They walked him about 15 feet and they forced him on the ground," LeBlanc said.

In LeBlanc's video, a police officer is heard yelling, "Stop resisting," and Begin replies, "I'm not resisting."

The video shows two officers holding Begin while a third drives his knee into him at least four times.

Barry MacKnight, the chief of the Fredericton police, said on Thursday afternoon that the RCMP will conduct a criminal investigation into Begin's complaint.

MacKnight said it is important that the Begin probe be seen as impartial and "as open as possible."

"This is a very important investigation. This is an important matter. We take all these complaints against our members seriously, in particular allegations of criminal wrongdoing," he said.

"So the investigation will take as long as it takes. Of course, part of my request to the RCMP, I'll tell you, is that all efforts be made to do it in a very timely manner."

MacKnight has suspended with pay one of two officers identified by name in Begin's complaint.

He said this incident, and another alleged assault on a soldier in May, do not "define" the members of his police force.

He also said there's no pattern of hostility between police and soldiers.

"Any implication that there is an ongoing systemic cultural problem between national defence employees and the Fredericton police is completely baseless," he told reporters on Thursday.

Complaint filed

In a written complaint, Begin says he did nothing to provoke the reaction.

Begin, who is teaching at the infantry school at CFB Gagetown and is normally posted at CFB Valcartier in Quebec, said he was mistakenly identified by bar staff as a customer who had caused problems two weeks earlier.

As he was leaving the club, he said a police officer asked to speak with him. Begin said he tried to explain that he was not the person they were looking for, saying he was not in Fredericton when the previous incident happened.

He said he was thrown to the ground and police officers started to hit him and knee him.

Andrew Bedford, another witness of the incident, said he read Begin's complaint on CBCNews.ca.

"What he was saying matched up with what I saw, and that what happened wasn't justified," he said.

"They said he was resisting arrest. I didn't see any resisting arrest."