Donna Irving, 29, and Warren Johnson, 46, originally faced second-degree murder charges in the death of Katelynn Sampson.

The little girl was found dead in an apartment in Toronto's Queen Street West and Lansdowne Avenue area on Aug. 3.

Irving -- granted custody of Katelynn last year as her mother, Bernice, battled a drug addiction -- had called 911 and claimed the girl had stopped breathing while choking on food, police said.

A police officer described Sampson's injuries as the worst he had seen in 20 years on the job, Canwest News Service reported.

Court documents showed that a background check on Irving was not conducted, CTV News reported.

Sampson's death was the city's 39th homicide of the year.