A man exposed himself to a young girl playing outside her house in Wellingborough.
The incident, in Gannet Lane, happened shortly before 2.30pm on Sunday, February 15.
The offender, who is believed to be of Asian appearance, was disturbed by the girl’s parents and ran off.
Officers are appealing for witnesses or anyone with any information to call Northamptonshire Police on 101.
Alternatively, they can call the independent charity Crimestoppers anonymously on 0800 555 111 or use the anonymous online form.