A Hollingdean pensioner has been missing since Saturday morning.
His carer last saw the 88-year-old man at 8.15am.
An unconfirmed sighting suggests that he may have taken a bus into Brighton at about 8.30am.
Sussex Police said that fears were growing for his welfare because he suffers from a number of medical conditions.
Aristide Polti from Lindfield Court, Hollingdean, has previously taken the train to South London where he has family.
Aristide, who is also known as Angelo, is white, about 5ft 5in tall, of slight build, with untidy short grey hair and a grey beard.
He talks with a slight Italian accent and walks with a three-wheeled walking aid.
He is thought to be wearing a brown jumper, red t-shirt, dark trousers and slippers.
He often wears a beige corduroy trilby hat.
Anyone who sees him or who has seen him since he disappeared on Saturday is urged to contact Sussex Police on 0845 6070999.