TORONTO - A mother who spent more than a decade behind bars for killing her toddler will likely be granted a new trial given the role disgraced pathologist Dr. Charles Smith played in her conviction 15 years ago.

Court documents released Monday show both Crown and defence are urging Ontario's top court to order a second hearing for Tammy Marquardt, who has always maintained her innocence.

Marquardt, 38, was given a life sentence after her second-degree murder conviction in 1995 in the death of her two-year-old son Kenneth Wynne in Oshawa, Ont.

Her lawyers argue she was the victim of a miscarriage of justice.

"Dr. Smith played a vital role in her trial and presented evidence that convinced the jury that Kenneth was a homicide victim, through smothering or strangulation," their factum states.

"The fresh evidence provides a natural cause of death related to Kenneth's epileptic condition that cannot be excluded as the cause of death."

In its brief to the Ontario Court of Appeal, which will hear the case Feb. 10, the Crown agrees Smith's evidence unfairly tainted Marquardt's trial and the case should be tried again.

However, the Crown's brief makes it clear prosecutors don't necessarily buy the seizure theory. It also suggests the child may not even have had epilepsy.

The problem with the conviction, the Crown argues, was that Smith's evidence made it impossible for the defence to argue at trial that the boy had died of "sudden unexplained death in epilepsy."

"While this was unlikely in the particular circumstances of this case, it should have been left with the jury," the Crown states.

Given the importance of Smith's now discredited evidence to the original finding of guilt, it is highly unlikely the Crown would in fact opt to proceed with a second full-scale trial.

In half-a-dozen similar cases involving Smith, the prosecution stayed or dropped the charges, or called no evidence at trial, leading effectively to an acquittal.

Marquardt, who had a troubled history that included substance abuse, told her trial she found Kenneth on Oct. 9, 1993, in bed tangled in his bedsheets and in distress. He was taken off life support three days later.

The Crown called her an impoverished, struggling young mother who suffocated her son in a moment of frustration.

Smith bolstered the prosecution with testimony that the boy was smothered or strangled.

At least five experts have since repudiated Smith's findings, suggesting as well that Kenneth may have died from an epileptic seizure.

The experts concluded the cause of death should have been recorded as "unascertained."

The case was finally reopened after a public inquiry savaged Smith's once stellar reputation in pediatric forensic pathology.

The defence argues the expert review and findings of the inquiry constitute "fresh evidence" that points to a miscarriage of justice.

The Supreme Court of Canada referred the matter back to the Ontario Court of Appeal to see if the conviction should be quashed.

Marquardt was released on bail almost two years ago pending the outcome of the appeal, which will be heard Feb. 10.

On Tuesday, the body that regulates doctors in Ontario will hold a disciplinary hearing to decide whether Smith should be stripped of his licence for professional misconduct and incompetence.