Police are investigating Peel Region's first homicide of 2013.

At about 3:45 p.m., Tuesday, someone called 911 about a woman on a balcony causing a disturbance at a townhouse complex on Colonial Drive, near Highway 403 and Winton Churchill Boulevard in Mississauga.

Police say when officers arrived, they found the woman barricaded inside the unit. Once they gained entrance inside, they discovered the body of a two-year-old girl. Police say there were obvious signs of trauma.

Police say the woman is the mother of the child and she was arrested at the scene.

24-year-old Teresa Amelia Williams has been charged with second-degree murder and is expected to make a court appearance on Wednesday afternoon.

Police have identified the victim as Evadne Williams-Scott.

Police will be canvassing the neighbourhood to see if they can figure out what led to the tragedy.