A murder investigation has been launched following the shooting of a man on Saturday night, police said.
The 31-year-old man was shot on Church Road, Hove, at about 11.30pm.
He was taken to the Royal Sussex County Hospital in Brighton but died just after 1am.
Chief Inspector Helen West of Sussex Police said the incident is not believed to be random.
"This is now being treated as a murder investigation. The man, who was found lying in the street, was quickly attended to by police and paramedics and taken to hospital but has tragically died.
"This is a fast moving, developing inquiry to identify and trace the person or people responsible. From information we do not believe this to be a random incident.
"We are actively seeking the offender, who we believe has left the area, and a number of police units including CID, Neighbourhood Policing, Road Policing and dog units are involved in this inquiry at this time. We are in the early stages of the investigation.
"We are talking with a number of witnesses and have secured the scene for forensic examination.
"Anyone who witnessed the incident or has information is urged to contact police on 101 quoting Operation Euro or the charity Crimestoppers anonymously on 0800 555 111.
"Church Road is closed between First Avenue and Selborne Road and diversions are in place. This will unfortunately cause some disruption well into Sunday while we investigate the scene but we appreciate everyone's patience," she said.