An Ottawa police officer at the centre of a brutality case that made national headlines more than four years ago pleaded guilty to assault yesterday and will be sentenced next week.

Const. Martin Cardinal, 28, was once convicted of needlessly pounding a woman's head on a police cruiser during a November 2000, arrest that was caught on videotape, but he was granted a new trial on appeal.

The retrial was set to begin yesterday at the Elgin Street courthouse, but after a series of in-chamber negotiations with two judges, Const. Cardinal's plea switched from not guilty to guilty.

The officer didn't talk to the media yesterday, but his lawyer, Michael Edelson, did.

"The events were almost five years ago, and it's been 41/2 years since he was charged," Mr. Edelson said. "My client wanted this resolved so he can move on with his life."

Mr. Edelson added there is no sentencing agreement with the Crown.

Const. Cardinal has been suspended with pay since being charged in the spring of 2001.

He also faces discipline charges under the Police Services Act stemming from the incident. These are scheduled to be dealt with when the criminal case is finished.

The assault was caught on videotape by a witness and first came to light when images from the tape were published in the Citizen.

The assault was committed by Const. Cardinal during an incident the night of Nov. 25, 2000, on Cambridge Street North in Centretown. The officer and a colleague were called to an apartment building about a disturbance.

On the building's front steps, the officers found Julie Cayer, 38, intoxicated and belligerent. Ms. Cayer was arrested, pepper-sprayed, searched and left with the young officer.

The video was shot from a balcony and captured what happened next.

It shows Const. Cardinal has Ms. Cayer bent over the rear of a cruiser when he grabs her by the hair with his left hand and her jacket near the shoulder with his right hand.

He appears to bash her head or face off the trunk of the car, look around, and bash her face again. Thumps can be heard each time her head makes contact with the car.

At the initial trial, Ms. Cayer, a woman with serious substance abuse problems and a lengthy criminal record, testified she didn't remember anything from the days leading up to the incident or afterward. However, she said she remembered her head hitting the trunk.

Const. Cardinal testified he was trying to give Ms. Cayer a couple of shakes to calm her down, and that it was his hand, which was gripping her coat, and not her head, that hit the cruiser.

Const. Cardinal maintains this position despite pleading guilty yesterday. Yesterday's agreed statement of facts did not mention Ms. Cayer's head hitting the trunk.

In the scenario to which he pleaded guilty, he thrust her head toward the trunk and thumps were heard.

That was enough for Ontario Court Justice Peter Griffiths to find the officer guilty.

"I find the facts support the plea that you have entered, and there is a conviction on the charge," the judge said.

At the initial trial, Ontario Court Justice Kent Kirkland said he was satisfied beyond a reasonable doubt that Ms. Cayer's head hit the car and this amounted to the use of excessive force by Const. Cardinal, so he convicted the officer.

The Crown asked for jail time. The defence asked for a discharge. Judge Kirkland granted the latter and ordered Const. Cardinal to perform 100 hours of community service.

However, on appeal, a new trial was ordered because Judge Kirkland made errors in his reasons for convicting the officer.