A 43-year-old man has been found dead in the early hours of Tuesday morning.

A member of the public discovered the man lying unconscious on the footpath of Alabama Ave in Prospect about 5.45am.

Ambulance crews rushed to the scene, but he could not be saved.

Acting Detective Superintendent Billy Thompson said the victim, of Bedford Park, was found with a "puncture wound" to his chest.

"We are still searching the area and we have not located a weapon at this stage," he said.

Detective Thompson believes the man was assaulted on the western side of Alabama Ave, close to Hillsdale St.

The victim is then said to have "staggered" up the street before collapsing and dying just off Prospect Rd.

He was found by a passer-by just minutes after the assault occurred.

Detective Thompson said officers are reviewing CCTV footage and continue to examine the scene and speak with neighbours.

Forensic investigators could be seen gathering evidence near Hillsdale St, about 200m away from where the body was found.

Police also used a sniffer dog and a drone to search the area.

"We appeal to any members of the public who were in the area at the time … from midnight last night through to about 7am this morning … to contact Crime Stoppers," Detective Thompson said.

Prospect Rd was closed to traffic as police searched for evidence the man's death but is now open.

Local resident Elliot Cragg saw the body while on his morning jog.

Mr Cragg started his run on nearby Galway St in Kilburn about 6am before he turned on to Alabama Ave and saw a long trail of blood.

"(The blood) was a good couple of feet from the body … the blood has obviously gone down the embankment there, so a bit of a disturbing scene unfortunately," he said.

"At that point I think he was pronounced dead … I literally walked right past it on the opposite side of the road."

Mr Cragg, originally from London, moved to Adelaide recently for a working holiday.

"When I moved to Australia obviously I didn't think that the situation would be happening on my doorstep."

The owner of local Vietnamese takeaway shop Lemongrass said the incident was "very concerning".

"My shop today looks like it has no business," she said. "This is very random, we've never had anything serious like this happen before. I was shocked when I came here (this morning)."

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