A man on his bike was robbed by a fellow cyclist in Kettering.
The incident happened between 9.45am and 10.15am on Friday, April 13, when the victim was riding his bike in Regent Street, near Crown Street.
The suspect, who was also on a bike, bumped into him and grabbed his rucksack causing the victim to fall.
The offender is described as a tall white man who was wearing green or grey trousers.
He made off in an unknown direction on his bike, believed to be orange or red in colour.
Witnesses, or anyone with information, are asked to contact Northamptonshire Police on 101 or call Crimestoppers anonymously on 0800 555111.