The pedestrian was struck by a silver-coloured vehicle travelling in the direction of Waitrose, opposite Lloyds Bank on La Route des Quennevais, around 12:45 on Sunday 20 March, officers said.
The Force is now looking to hear from anyone who saw what happened or has dash-cam or video footage.
Pictured: The area Police said the collision occurred.
Anyone who can help should call 612612 or make an anonymous report with Crimestoppers by calling 0800 555 111 or using their online form.