A 14-year-old boy was robbed by a gang of youths who threatened him with what was thought to be an imitation fire arm.
The four men, believed to be Somalian, threatened the teenager until he handed over his Blackberry Bold 9900 during the attack in an alley between Queensway and Leon recreational park in Bletchley.
The offenders then ran off towards Queensway after the attack, which happened at around 3.20pm on Wednesday.
The first offender in his mid to late twenties, approximately 6ft, of average build, with spiked up black hair and stubble. He wore a black leather jacket with a light coloured top underneath, jeans and sunglasses.
The other men all wore jeans and hooded tops.
Anyone with information should contact PC Steven King from Milton Keynes police station via the Thames Valley Police Enquiry Centre on 101.
If you don’t want to speak directly to the police, you can contact the independent charity Crimestoppers anonymously on 0800 555 111 or online at Crimestoppers-uk.org No personal details are taken, information is not traced or recorded and you will not go to court.