VANCOUVER -- An investigation is being ordered after witnesses say Vancouver police struck a man with an unmarked car, grappled with him and Tasered him during an interaction that began over bylaw violations – not wearing a helmet and biking on the sidewalk.

At least four videos taken by passersby and obtained by CTV News show a bike on the ground along East 6th Avenue just after midnight on Wednesday morning, and various angles of a struggle that goes from the road to inside a police vehicle and back again.

Witness Andrew Louzi described the scene as an astounding overreaction to bylaw violations.

“They could have killed him,” Louzi said.

Vancouver police tell a different story, saying the man struck their officers and tried to steal the police vehicle in the struggle. He's now facing charges, including assault and theft of a motor vehicle.

Officers at the scene told onlookers the 35-year-old man was also wanted on outstanding warrants.

Police spokesperson Sgt. Aaron Roed told CTV News that the initial bylaw violation was serious enough for officers to take action — and it became criminal when the man fled and resisted arrest.

“Our officers don’t intend to be assaulted or punched in the face dealing with a bylaw infraction,” he said.

Another witness, David Mattatall, said he was meeting some friends at the intersection nearby when he saw an unmarked police car with no headlights on start to tail the bike just after midnight.

“They made a few attempts to knock him off his bike, speeding and slowing. Then they floored it and hit the accelerator,” Mattatall told CTV News.

Mattatall and Louzi recorded much of the encounter with their phones. “We all saw the police car strike the cyclist. The cyclist is hit and falls over the side of the police car. The police officers get out and start beating on the cyclist," Louzi said.

Mattatall’s video begins with the three men grappling outside the police car. One of the plainclothes officers appears to kick the man, who wrests himself free of their grip. They push him into the driver’s seat.

Another video, taken from across the street, shows the car's engines being revved, its lights and sirens turning on and off, and the horn going as the man yells inside. “Out of the car, asshole,” one of the officers yells.

More police officers arrive. One of them yells, "Taser!" and the weapon discharges. The man is pulled out of the vehicle onto the ground, where he is kneed and punched by other police officers.

"You guys hit me with your car!" the man yells in the video. "Hands behind your back!" another officer says. "OK. I can't breathe," he says.

Mattatall yells for one officer to get his knee off his neck, and that officer denies that his knee is on his neck.

"You ran over a dude and you're now on his neck," Mattatall says, asking one of the new officers who showed up on the scene to arrest the police car's driver.

"That's not how this works," the officer says. "You don't care about the law?" Mattatall responds.

In an emailed statement, Sgt. Roed said the cyclist didn't comply when officers tried to stop him over the blyaw infraction.

"Officers instructed the bicyclist to stop. After officers identified themselves, the cyclist then ignored the commands and tried to flee from police," Roed said.

"The cyclist was stopped a short distance later at which time he began to fight with the officers. During the arrest of the accused male, he punched the officer in the face multiple times and jumped into the driver's seat of the police vehicle. The man tried to steal the police car and revved the engine in an attempt to get away."

Roed said the man was taken into custody "after a struggle." Police recommended the following charges to Crown against the 35-year-old: obstructing a police officer, failure to comply with a release order, assaulting a peace officer, theft of a motor vehicle and flight from police.

But Louzi and Mattatall say they didn’t hear any warnings from the unmarked car, and their video doesn’t show punches by the arrested man.

Mattatall says he’s provided his video and others to the office of B.C.’s Police Complaint Commissioner, which told CTV News it’s going to ask the VPD to investigate what happened.

Police are allowed to use reasonable force to do their duties, and can also use force in self-defence. But if the force isn't reasonable, officers can face discipline under the Police Act and also could face criminal charges.

A bylaw infraction isn’t worth hitting a cyclist and doesn’t justify the level of force used, Mattatall said.

“That could have been any one of us,” Mattatall said. “They were treating him as if he was a punching bag. That’s not right.”