New charges have been laid in the 1997 death of a toddler, one of the dozens of questionable cases handled by discredited pathologist Dr. Charles Smith.

Brenda Waudby of Peterborough, Ont., was originally charged in the beating death of her 21-month-old daughter, Jenna Mellor. The charges were dropped two years later, after the Crown found a shift in medical opinion.

On Thursday, Peterborough police charged a 23-year-old man with second-degree murder and two counts of sexual assault. The man was 14 years old at the time of the child's death, so cannot be identified under the Youth Criminal Justice Act.

Forensic testing by the FBI and other agencies led to his arrest. Police said he is known to the family.

A total of 44 of Smith's cases in Ontario have been placed under review after an audit of his work found missing forensic samples and misplaced blame.

A pubic-like hair found on Jenna Melor's body went missing during Smith's investigation. He kept the hair in his office for five years before it was seized by police.

Waudby also complained to the Ontario College of Physicians and Surgeons that Smith hadn't conducted a standard rape kit test during the autopsy.

Smith's work was used in at least two other child death cases in which family members were charged.

In one case, a man from Sault Ste. Marie spent 12 years in prison after being convicted of sexually assaulting and murdering his four-year-old niece.

William Mullins-Johnson was released on bail in September after other forensic experts said the girl died of natural causes and had not been sexually abused.

In a Kingston case, a mother was charged with murdering her seven-year-old daughter and spent two years in custody after Smith told police he believed the girl has been stabbed repeatedly with a pair of scissors.

The charges were dropped two years later, after two expert witnesses said a pit-bull terrier likely caused the wounds.

Smith, a native of Saskatchewan, recently had been working at Saskatoon City Hospital on a short-term contract to perform non-legal autopsies. However, the Saskatoon Regional Health Authority said earlier this month it would not hire him permanently because of the review.