Police are appealing for witnesses after a 12-year-old boy was asked for the time by a man who then stole his phone.
The victim was walking along Cambridge Street, Derby, at about 7pm on Sunday, July 13 when he was approached by the offender.
The robber asked him for the time and, when the victim took out his phone to check, he grabbed it and forced him to put his passcode in.
He then made off with the black iPhone 4 towards Normanton Road.
The robber was white, aged in his late-teens or 20s, about 5ft 8ins and of slim build. He wore a grey baseball gap, grey zip-up hoodie and black jogging bottoms.
Witnesses or anyone with information on the offence should call Derbyshire police on 101, quoting incident 700 of July 13.