An Alberta woman charged with murder in the death of a foster child was also caring for two other children at the time the 21-month-old girl died in early March, according to sources.

Christine Laverdiere, 34, has been charged with second-degree murder in the death of the Morinville toddler.

The little girl was taken to hospital in Edmonton on March 1. She died two days later. Police have not released a cause of death but sources familiar with the case have told CBC News the child likely succumbed to injuries caused by shaken baby syndrome.

Laverdiere also had two other children in the home at the time, age three and 18 months, respectively. One of the children was her own.

CBC News was told by the victim's biological family that the girl's mother had expressed concern about Laverdiere and complained about seeing bruises on her child's body. 

A doctor apparently examined the child at the time but dismissed the concerns.

In Morinville, a neighbour of Laverdiere's described her as quiet and not interested in participating in community activities.

Trevor Shandro said he saw an ambulance arrive at Laverdiere's house in March but other than that, didn't know much about the case.

"I don't think a lot of people know about it because it was quite quiet," he said. "The government didn't reveal addresses or so forth. My wife from the front window saw a child being wheeled out in a stretcher unconscious."

Laverdiere had been a foster parent for less than two years. She made a brief court appearance on Monday and is scheduled to return to court in Morinville on June 24. She remains in custody.

The foster child cannot be named under Alberta's Child, Youth and Family Enhancement Act, which stipulates that the identities of children in care be protected.