A woman was robbed of her handbag after she was pushed over near Norfolk Square, Brighton, in the early hours of Sunday 5 June.
The 21-year-old was shoved from behind and as she fell she dropped her bag which was snatched by a man who came running up to her.
He was with another a man and a woman and they had been drinking in Norfolk Square. The robbery happened around 1.25am and the victim suffered cuts to her knees.
The main suspect was described as white, aged in his late twenties, 5ft 8in tall, of slim build and was wearing a black hoody and dark coloured jeans.
The woman was described as being in her late thirties, 5ft 3in, of very skinny build with light brown hair tied in a pony tail and had a gaunt and pale complexion.
She was wearing baggy clothes, light coloured jeans and a white hooded top.
The three remained in the area even though the victim was on the phone to the police. She left the area as she was frightened.
Anyone with information should contact Sussex Police on 0845 6070999.