A personal dispute between two families might have led to an Albanian father being shot dead during a visit to the seaside.
Xhem Krasniqi, 31, was hit once in the abdomen after a gunman opened fire in Church Road, Hove, East Sussex, at about 11.30pm on Saturday.
The married scaffolder, who lived in Kent, was taken to the Royal Sussex County Hospital in Brighton but died just after 1am, Sussex Police said.
Shots were also fired at Mr Krasniqi's brother and nephew, leading detectives to treat the case as a murder and two attempted murders.
Detective Chief Inspector Jeff Riley said: "We believe the men all knew each other and we are open minded as to the motive.
"The initial indication is that there's a personal dispute between some members of two families and that this has escalated dramatically, leading to Xhem's tragic death."
Police said yesterday that an all-ports alert had been issued amid concerns that a person officers want to question in connection with the shooting could leave Britain.