Gwent Police are appealing for information to find 18-year-old Joseph Bellamy from Monmouthshire.
Joseph was last seen leaving his home address in Caldicot between midnight and 1am on Tuesday 3 December.
He was later captured on CCTV cycling on a red pushbike towards the M48 bridge.
Joseph is described as white, 6ft tall with mousey hair and blue eyes.
He was last seen wearing light colour jeans with black high top Nike trainers and a black Teddy fleece jumper with a black sweatshirt underneath.
Anyone with information on his whereabouts is asked to Gwent Police on 101.
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