Update after young man's body found on Barrpowell St, Welland in Adelaide trends now

Police are paying close attention to a skateboard, tyre tracks and a pool of blood at the scene where a body has been found in Adelaide's inner suburbs.

Emergency services were called about 1.30am on Wednesday to a street in Welland in the city's inner northwest, finding a 21-year-old man unresponsive on the roadway of Barrpowell St.

South Australian Police Detective Superintendent Des Bray said the young man was murdered and the police suspect the victim and offender knew one another.

'This young man, we believe, arranged to meet somebody, in this street, at 1.30am. On that basis, we do not believe this death was committed by some random stranger,' he said just before midday.

'I am confident, given that the majority of murders are solved in this state, I have no doubt we will get to the bottom of this. And we've got a large number of detectives and uniformed people working across Adelaide at the moment.'