A witness testifying at the trial of a prominent Pembroke dentist charged in a fatal 2011 crash said she saw a woman on the night of the crash stumbling in the parking lot of a Kanata bar before getting into her SUV.

Tuesday was the first day of the trial of Dr. Christy Natsis, who is charged with impaired driving causing death, dangerous driving causing death and exceeding the legal blood-alcohol limit.

She has pleaded not guilty to the charges.

Mersiha Mesic, 26, told an Ottawa courtroom a woman matching Natsis's description appeared intoxicated as she left The Crazy Horse bar. Mesic said the woman was arguing with a man before she got into a black Ford Expedition and drove off.

Mesic said she ran after the Expedition trying to stop the driver — but was unsuccessful.

Less than an hour later a black Ford Expedition was involved in a fatal head-on collision on Highway 17 near Arnprior that killed 50-year-old Brian Casey of Ottawa. Casey was on his way home after working that night in Chalk River, Ont.

Mesic was not able to positively identify the woman she saw as Natsis, and she said police never showed her Natsis in a lineup photo.

Earlier in the trial Crazy Horse waitress Laura Bateman testified she served a woman matching Natsis' description two eight-ounce glasses of Chardonnay and an order of chicken wings but said the woman did not appear intoxicated.

Bateman was also unable to identify Natsis in the courtroom.

The trial continues Wednesday.