A teenager suffered a serious facial injury after he was kicked off his bike and slashed in the face with a knife on a footpath in Northampton.
The victim, a 17-year-old boy, was riding along the A45 Nene Valley Way cycle path, near Billing Aquadrome, when someone called out to him.
When he stopped, the offender kicked the bike, took a knife out and slashed him in the face, causing a wound that required medical treatment.
The assault happened at about 9pm on Sunday (28 February), next to a wooded area.
The offender, who is described as male, and wearing a black tracksuit and black face-covering, ran off towards Billing Aquadrome.
Officers are appealing for witnesses and anyone with information is asked to call Northamptonshire Police on 101. Alternatively, they can call independent charity Crimestoppers anonymously on 0800 555111.