Mounties in Williams Lake, B.C., are being accused of a pattern of excessive force after the release of surveillance video showing several violent encounters between RCMP and young First Nations men inside the detachment.

The videos are silent, but even without sound, the BC Civil Liberties Association says it's clear that Curtis Billy had a rough time when he was placed in a holding cell on Aug. 27.

The detachment head, Staff Sgt. Warren Brown, is shown leading the charge in taking Billy to the ground after guards apparently give him a lecture for covering the surveillance camera with a wet paper towel.

"There's no threat, and then Brown grabs his head and drives him into the ground," BCCLA director David Eby told CTV News.

"I think they were really frustrated and annoyed, and in fact the detachment head has a long history with this guy. It's difficult to know what the motives are."

Billy was taken to court with injured ribs and a bleeding head wound.

A second video shows a May 6 incident in the booking area of the same detachment. The BCCLA says that Oren Mostad was asking for the return of two confiscated hunting rifles.

In the footage, he exchanges words with an officer, who then takes him to the ground, where he is repeatedly punched.

Mostad was charged with assaulting a peace officer.

RCMP say, however, that Mostad was being booked on firearms and domestic assault charges, and allegedly refused to allow officers to search him or take his photograph.

Another video taken in January shows an intoxicated man, Lloyd Gilbert, held in a restraining chair for three-and-a-half hours. He wets himself before being finally released without charges.

BCCLA sees a pattern of excessive force being used by officers in the detachment, and is particularly concerned because all three men are First Nations.

"If they think that this stuff is okay-- that they can justify it by use of force policy or media policy or whatever policy they want -- then that's a call they're going to make. The problem is they're losing the community in Williams Lake," Eby said.

RCMP Insp. Tim Shields says that an investigation has been launched into the videos.

Although he acknowledges that more work needs to be done and officers should show respect, he says there is a limit.

"If that person starts swearing in our face and telling us there's no way they're going to leave a cell or be fingerprinted or photographed, yes, we're going to use force," Shields said.

The RCMP is asking the public to reserve judgment until the investigation is complete, pointing out that without any audio from the surveillance cameras, there might be more to the story.

Shields says that in the January video, Gilbert was told numerous times to stop jumping on top of the sink numerous times.

"He kept getting back up and endangering himself. This is the type of subject the restraint chair was made for. It saved him from hurting himself," Shields said.

With a report from CTV British Columbia's Peter Grainger