Casey Crime Investigation Unit detectives are investigating following a robbery in Endeavour Hills earlier this month.
Investigators have been told an Apple iPhone was advertised for sale on Facebook and the offender contacted the victims asking to see the phone.
The male attended the victims address on Chalcot Drive on Monday 13 July about 3.20pm.
The male was given the phone to check out and after a short time attempted to run.
The victim and the man struggled and as a result the victim was thrown to the ground.
The offending man ran to a nearby blue grey Subaru station wagon and fled.
He is described as African in appearance, 17-20 years, 180cm tall with a thin build and a distinct 2.5cm cut or scar above his left eye.
He was described as wearing a black or navy hoody, athletic pants and blue runners with a white sole.
Police have released a picture of a male they believe may be able to assist them with their enquiries.
The victim was taken to hospital with a serious arm injury.
Anyone who witnessed the incident or with further information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au
