Police from the Kent and Essex Serious Crime Directorate are appealing for the driver of a white van to come forward because they may have information that could help with the investigation.
On Wednesday (22 November), Joe Daniels, 58, was found unresponsive inside his pub, the Red Cow, Foord Road, Folkstone, Kent, shortly before 11.30am.
He had suffered an injury consistent with a gunshot and was pronounced dead at the scene. A firearm was also recovered, according to police.
The white van was parked on the pavement outside the pub between 9.30am and 10.30am, police said.
The driver is described as white, heavily built, between 30 and 50 years old, 5ft 10in and as having short dark brown hair.
Senior investigating officer Detective Chief Inspector Richard Vickery said: "There is no suggestion the driver of the van has done anything wrong but the van was parked there just before the incident happened, and we are hopeful he may have seen or heard something that could aid our investigation.
"We would like to thank all those people who have called us so far and provided us with information including dash cam footage. As we continue our enquiries into the circumstances behind Mr Daniels’ death, we would really like to hear from anyone else who may have information."
Witnesses can call Kent Police's appeal line on 01303 289600 quoting reference 22-0452 or Kent Crimestoppers anonymously on 0800 555111.