As C-Store went to press Anthony Gurney, 36, of Balham, South London, was due to appear before magistrates in South-west London. He has been charged with attempted murder, robbery and firearms offences.
Two men have already appeared in court in connection with the robbery, which took place last month at the Premier store on Margery Road, Hove.
Stephen Gurney, 35, from Putney, South London, and Henry Doyley, 42, of Sheridan Terrace, Hove, have both been charged with robbery.
Store owner Caesar Zarate suffered injuries to his face and hand during the attack which took place in front of terrified customers.