A second child allegedly stabbed by their mother in the Blue Mountains at the weekend has died
Three children and the 42-year-old woman were found injured in a car on Waratah Rd at Valley Heights about 12.45pm on Sunday.
Nothing could be done to save the oldest child, aged five, and a one-year-old and three-year-old were rushed to hospital.
NSW Police confirmed on Thursday the baby had died.
The three-year-old remains in a critical condition in hospital.
Police charged the mother, who they said had self-inflicted injuries, with murder (DV) and two counts of grievous bodily harm with intent to murder (DV).
The woman, who has not been named for legal reasons, was refused bail during a court appearance on Tuesday.
She will now face an additional murder charge when she appears in Penrith Local Court on November 20.
7NEWS understands the alarm was raised when a cyclist came upon the family’s vehicle with its doors open.
Members of the public provided first aid and contacted triple-0.
The children’s father was reportedly at work when told the news.
If you or someone you know is impacted by sexual assault, domestic or family violence, call 1800RESPECT on 1800 737 732 or visit 1800RESPECT.org.au.