A teenage girl was assaulted as she walked along a Corby street.
The girl was walking along Rockingham Road at about 5.35pm on Saturday, September 5, when she realised she was being followed by a teenage boy.
He grabbed her by the arms then slapped her before running away.
He was between 15 and 16, 5ft 6in to 5ft 7in and had short, dark, straight brown hair.
He was wearing grey jogging bottoms, a grey top and white trainers.
Witnesses, or anyone who knows anything about this incident, can call Northamptonshire Police on 101.
Alternatively, they can call the independent charity Crimestoppers anonymously on 0800 555 111 or use the anonymous online form at www.crimestoppers-uk.org.