A man has died after he was shot in the chest outside a filling station.
John Pordage, 34, was standing with another man, 25, outside a garage in Chelmsford when they were fired at from a car at about 02:10 BST, police said.
Detectives said they believed the victim, who lived in Galleywood, Essex, knew his killer and was targeted.
A local resident told how he performed CPR on the victim, who was shot by someone in a blue Ford Fiesta which then drove off.
Essex Police said the shooting took place at the BP garage on Baddow Road, near the Army and Navy roundabout, in the town.
Ch Insp Ronnie Egan said although such incidents were "rare", she understood people would be concerned and extra patrols were being put in place in the area.
"It does involve people who were known to each other," she added.
"My local teams are out working both with the investigators and the community groups to reassure and provide additional visibility in the Great Baddow area at this stage."
Joe Lamb, who lives close to the scene, said he performed CPR on the victim for 15 minutes before an armed police unit and ambulance arrived.
"I heard a couple of bangs... and heard a guy screaming in the street saying 'help me', so I came running out and ran up to the garage," he added.
"There's a guy spread-eagled on the floor.
"When he lost consciousness I performed CPR for the next 15 minutes until the ambulance arrived."
The injured man was taken to hospital where he later died.
Baddow Road remains closed for a forensic examination of the scene.
Police are appealing for witnesses and anyone with information or footage of the incident to call 101.