Just after 11.30pm last night a man threatened Pooraka Service Station staff saying that he had a knife and demanded money.
Staff handed over a small amount of cash and the man was last scene walking towards Diagonal Road.
He also took some drinks before leaving and walked past two people filling up their cars with fuel at the time.
He is described as being of Aboriginal appearnace, wearing a dark grey hoody with a round logo on the front, black trackpants, with three adidas stripes down the side, dark grey sneakers and a baseball cap. He had a chubby face, 5′ 8″ (about 172cm).