The arrest of a teenager on Vancouver Island this past weekend has sparked criticism of an RCMP officer, but police say the cellphone video released by a witness doesn't tell the whole story.

The incident happened on Saturday in the town of Cumberland after an officer apparently approached a youth for riding a bike without a helmet.

The video, posted to social media, contains different cellphone camera angles edited together.

A youth and adult female are facing charges of obstruction in relation to an incident in Cumberland on Vancouver Island. (CBC)

It shows the officer sitting on the youth while a woman in close proximity yells at the officer.

Bystanders are also heard to be yelling at the officer. At one point the youth being held down yells, "That's my neck."

Witnesses accused the officer of using excessive force, but the Comox Valley RCMP claim in a release that the youth "allegedly refused to identify himself and become (sic) verbally abusive with the officer."

"In accordance with the Criminal Code, the male was arrested for obstruction. When attempts were made by the lone officer to restrain the male, he allegedly continued to struggle," the statement reads.

"This is no different than a driver of a vehicle being pulled over for a traffic violation and refusing to provide their name or drivers licence." said Detachment Commander Inspector Tim Walton.

"While a few people in the video are very vocal, an independent witness contacted our detachment afterwards to comment on our officer's patience throughout."

"These situations can be very challenging for an officer who is alone among a group of arguably volatile people," stated Walton. "I'm very pleased that nobody was hurt."

The youth has been released on a promise to appear. An adult female is also facing a charge of obstruction.