The City of Edmonton has been granted intervener status in the appeal of a peace officer convicted of assault causing bodily harm in a violent arrest of a jaywalker.

Peace officer Robert James Sevigny was charged on May 3, 2017, after using a technique known as a straight arm bar takedown to arrest a jaywalker who was walking away from him.

The intoxicated man suffered a laceration to his forehead and a dislocated thumb during the takedown.

The case went to trial in October.

Provincial court Judge D'Arcy DePoe found Sevigny didn't have the lawful authority to arrest the jaywalker without a warrant, and that his use of force was an assault causing bodily harm.

Sevigny was sentenced in April to 12 months of probation and a 10-year firearms prohibition.

He is appealing his conviction on two grounds: that the trial judge erred in determining that he had no lawful authority to arrest the jaywalker, and in determining that bodily harm was a foreseeable result of his actions.

The City of Edmonton, which employs about 140 peace officers, asked for intervener status at the Appeal Court of Alberta on the first ground only.

The city claims DePoe's decision creates uncertainty around when peace officers have arresting power.

"It will argue that the arrest powers under [the Provincial Offences Procedure Act] and the [Traffic Safety Act] are complementary and that the existence of the latter does not implicitly exclude the former," the city said in a submission to the appeal court.

The takedown

Sevigny, 30, was a transit peace officer at the time of the offence.

He was on patrol with a partner when he witnessed a man crossing 102A Avenue against the red light at the intersection of 100th Street, according to a partial transcript of the trial.

Sevigny approached the man and informed him that he was jaywalking.

The man became loud and angry, swore at the peace officer, and started walking away.

Sevigny took the man down without warning, prompting him to hit the concrete sidewalk head first.

A witness described the impact "like a watermelon hitting the floor of a grocery store."

"Even though [the victim] had been verbally aggressive, he was not described as physically aggressive in any way and, in fact, was walking away from the accused when he was taken down," DePoe said.

Sevigny testified that he had taken down the man because he anticipated a physical confrontation and believed he had the authority to arrest him.

DePoe disagreed, pointing out the Traffic Safety Act only grants peace officers the authority to arrest a jaywalker without a warrant if the person refuses to identify themselves.

Sevigny hadn't asked the jaywalker for identification prior to the takedown, according to the transcript.

"Without the officer actually making a request for identification, the accused had done nothing to that point which made him arrestable," DePoe wrote.

The judge subsequently found Sevigny guilty of assault causing bodily harm.

The appeal

Sevigny's argument that the judge made a mistake in determining he didn't have the authority to arrest is based on the Provincial Offences Procedure Act.

According to the act, a peace officer can arrest someone without a warrant if the person has contravened a provision contained in a provincial act.

As jaywalking is regulated by a municipal bylaw, it falls under the Municipal Government Act, the appeal argues.