Police are concerned for a Lancing teenager who has been missing since Saturday (February 2).
Ali Yunes Ahmed, 16, has not returned home after saying he was getting on a train to see friends in Bognor Regis, police have said.
Sussex Police believed he may have travelled to London and has links to Chichester, Bognor Regis, and Brighton.
Ali is North African with black hair and is slim.
Anyone who has seen him is asked to contact police online quoting serial 1207 of 02/02.