Melbourne Embona Taskforce detectives are appealing for information following an attempted robbery in Melbourne last month.
Detectives have been told the victim and his friend were approached by three unknown men in Batman Park about 1pm on 24 July.
One of the men of grabbed the victim's necklace and threatened to strike him if he did not hand it over.
The victim refused and the man struck him in the upper body, breaking the necklace.
The victim and his friend ran from the scene.
The group of men continued on foot and were last seen walking east along Flinders Street.
Investigators have released images of three men they believe may be able to assist with their enquires.
The first man is perceived to be Caucasian in appearance, approximately 20-25 years old, of average height and build and has a light-brown mullet.
He was seen wearing a green baseball cap, a gold puffer jacket, torn jeans, and red runners.
The second male is perceived to be Caucasian in appearance, approximately 20-25 years old, of average height and build and has short dark hair.
He was seen wearing a grey Calvin Klein hooded jumper, a black puffer jacket, tan shorts, and black runners.
The third male is perceived to be Caucasian in appearance and approximately 30 years old, of average height, skinny build and has medium length brown hair.
He was seen wearing a black FILA jumper, black Nike tracksuit pants and black and white Nike runners.
Anyone with information or any witnesses is urged to call Crime Stoppers on 1800 333 000 or log onto www.crimestoppersvic.com.au.
