A 12-year-old boy was assaulted in Banbury as he was cycling to school with a friend last Thursday.
It happened at about 8am as they crossed Middleton Road when a man grabbed his arm and pushed his bike into the road.
The offender then walked off towards the railway station.
The boy was not injured and nothing was stolen.
The offender is white, 5ft 7ins, slim build and in his forties. He was wearing a dark coloured beanie hat covering most of his brown hair, a brown waist length coat and faded blue jeans. He may have an Australian accent.
PC Adam Feeney, from Milton Keynes police station, said: “The boys were on their way to school when this incident happened in the centre of the pedestrian crossing at the traffic lights junction of Bridge Street and Lower Cherwell Street.
“I would like to hear from anyone who witnessed it or can help us identify the offender.
Anyone with information should call the Thames Valley Police 24-hour enquiry line on 101, or Crimestoppers anonymously on 0800 555111.”