Gwent Police are appealing for witnesses after a car reportedly came off the road and crashed into a tree in a ditch near Llanbradach.
The incident happened on the A469 at around 6.20pm on Tuesday, April 2.
The driver of the car, which was a blue Vauxhall Corsa, was unharmed.
However, police believe a silver Mercedes may have been involved in the incident but left the scene.
Anyone with information or dash cam footage can contact Gwent Police on 101, quoting log 417 of 2/4/19.
Alternatively, Crimestoppers can be contacted anonymously on 0800 555 111.