Rockingham Detectives have released a picture of a man wanted over an alleged robbery.
Two boys, aged 14 and 15, were followed to an underpass near Read Street just after 2.20pm on December 13.
An unknown man demanded their property and threatened them with a knife.
One of the victims ran away and the man walked off.
He is described as light skinned, aged 17 -20 years, short light coloured hair, black t-shirt, black Adidas shorts, black thongs/sliders and black socks.
He also had a black shoulder bag.
Anyone with information is asked to call Crime Stoppers on 1800 333 000 or report online at www.crimestopperswa.com.au.