Two 15-year-old boys were targeted by two other teenagers who threatened them and took their bike.
The boys were walking through The Arbours pocket park from the direction of Kendal Close, at around 4.30pm on Tuesday this week when they were approached by two teenagers coming from the opposite direction.
One of the teenagers pushed one of the boys and threatened him before stealing his bike and riding off in the direction of Northampton College, Booth Lane.
The offender is described as black, around 16 years old, 5ft 4in, of skinny build, with a cloth covering his face and wearing a black Nike tracksuit and black trainers.
The second teenager is also described as around 16 years old, black, 5ft 5in, with a hoodie pulled over his face, of stocky build and wearing a black tracksuit with blue stripes down the legs.
The stolen bicycle (pictured) is a sliver and red Carrera with a silver, red and grey saddle.
Anyone with information can contact Northamptonshire Police on 101. Alternatively, they can call the independent charity Crimestoppers anonymously on 0800 555 111.