A girl on her way home from school in Rushden was left with a broken jaw after being attacked.
The victim, aged just 15, was walking in Greenway between 3pm and 4.10pm yesterday (Monday) when the shocking incident took place.
She was next to the disused railway track between The Hedges and Spire Road when she was was approached by a man, who police said was unknown, who tried to lift up her skirt before attacking her.
Her punched her in the face and kicked her, causing her teeth to be pushed back into her jaw. It has since been confirmed her jaw was broken.
She was also left with cuts to the inside of her mouth, a fractured nose and a potential fractured cheekbone
A police spokesman said: "The offender is described as a mixed race man in his mid 20s, about 6ft 1in, of muscly build and with short dark hair.
"He was wearing a white top and black trousers or jeans."
The spokesman added that it was believed to be a random attack.
Nothing was stolen from the girl and no arrests have yet been made.
Witnesses or anyone with information should contact police on 101 or Crimestoppers anonymously on 0800 555111.