Gwent Police are appealing for information to a fatal road traffic collision that happened at about 1.45pm on Saturday 5 February.
It involved a car and a van on the M4 westbound, between junction 28 and 29.
The four occupants of the car were all taken to hospital.
A four-year-old girl has since died, and a three-year-old boy remains in a critical condition. A woman remains in hospital in a stable condition and a man has been released.
The 41-year-old man, driving the van, was arrested and has since been charged with causing death by dangerous driving and two offences of causing serious injury by dangerous driving.
The motorist appeared before Newport Magistrates Court yesterday.
Anyone with dash-cam footage, or who has any information that could help the investigation, is asked to call police on 101 quoting 2200041245, or you can direct message via Facebook or Twitter.
