A 14-year-old boy was robbed by a gang of up to 10 youths in Northampton before he ran away.
The victim was approached in Mill Lane, Kings Heath sometime between 6pm and 7.30pm last night (Wednesday, September 20).
Two of the offenders asked him first to hand over his bike and then his mobile phone before the victim then ran away.
A spokeswoman for Northamptonshire Police said: "One of the youths was white, aged about 15 and was 6ft with a skinny build. He was wearing a dark baseball cap with a black mask and an Adidas tracksuit.
"A second teenager was described as mixed race, aged about 14 with a skinny build and an Afro-style haircut. He was wearing a black tracksuit and had a pair of shoes under his jacket
"A third male was described as white, 5ft 7in and skinny with short blonde hair and he was wearing a grey tracksuit with the hood up and black gloves.
"At least one girl was in the group, described as white, aged about 14 with a medium build, blonde hair in plaits and wearing a blue tracksuit and white shoes."