Second child dies after alleged Blue Mountains stabbing as mother faces additional murder charge

Police and emergency services at the scene of the alleged stabbing in the Blue Mountains, west of Sydney, on Sunday. Photograph: Sarah Wilson/AAP

A baby has died in a Sydney hospital five days after a mother allegedly stabbed them and two other children in the Blue Mountains, police say.

Bystanders were first on the scene after finding the three children and the 42-year-old woman with stab wounds inside a vehicle at Valley Heights in the Blue Mountains, west of Sydney, on Sunday afternoon.