Muggers stole a black iPhone from a 17-year-old Brighton College student at about 11.30am on Saturday morning (11 October).
Sussex Police said: “The victim left the college’s side entrance in Sutherland Road, Brighton, and walked along Craven Road towards his car, parked in Parham Close.
“As he turned into Parham Close, he was approached by two men who demanded he hand over his mobile phone. They also threatened to take his wallet and car.
“But the pair then ran off via Craven Road and Sutherland Road. One was white, and one of Asian appearance. A third man, possibly acting as a look-out, is also thought to have been in the area.”
Anyone who saw what happened or who may have other helpful information is asked to email phone Sussex Police on 101, email email@example.com or contact the independent charity Crimestoppers free and anonymously on 0800 555111.