A year after their mother was found drowned in her bathtub, two Mississauga sisters have been charged with first-degree murder.

Investigators initially found no evidence of foul play in the 44-year-old woman's death on Jan. 18, 2003.

Peel Regional Police reopened the case after they received new information in December.

The sisters, who were 15 and 16 when their mother died, were arrested Wednesday.

They cannot be identified under the terms of the Youth Criminal Justice Act.

The victim's name and address cannot be released to protect the identities of the accused.

The girls were scheduled to appear in a Brampton court Thursday.