A 23 year old man from Kettering received serious head injuries after being hit with a baseball bat on Cedar Road.
The victim tried to intervene in an altercation between two men at around 9pm on Saturday, 25th October, but whilst doing so he was struck on the back of his head with a baseball bat.
He received treatment at Kettering General Hospital, but was later transferred to the John Radcliffe Hospital in Oxford with serious head injuries.
The offender is described as a white man in his late twenties with untidy shoulder-length hair.
A man has been arrested in connection with the incident, and has been released on bail pending further enquiries.
Witnesses or anyone with any information can call the police on 101 or Crimestoppers anonymously on 0800 555 111.
By Stephen Matthews