A 13-year-old boy was slapped by an unknown man as he sat in a park in Corby.
The incident took place in the park next to Kingswood Community Centre shortly before 9pm on Sunday, 3 July.
Now, more than a month on, police are appealing for witnesses to come forward.
The teenager was sat on a swing in the company of friends when he was approached by an unknown man who was with a small child.
The man slapped the teenager and pushed him to the floor before leaving the park and heading towards the Kingswood Estate.
The offender was a black man, aged in his 30s, about 5ft 6ins and of thin build, with short dark hair.
He spoke with a London accent and had a small sword tattoo on his neck.
Witnesses or anyone with information about this incident can contact police on 101 or Crimestoppers anonymously on 0800 555111.