A man was taken to hospital after he was beaten up with a baseball bat in Wellingborough.
Police were called at about 7.20pm on July 2 after the incident in Masefield Close.
A 36-year-old man was arrested on suspicion of assault causing actual bodily harm. He has since been released under investigation.
The victim, a 58-year-old man, was taken to Kettering General Hospital. A police spokesman said he suffered three fractured ribs, two suspected fractured ribs and a broken finger.
Witnesses or anyone with information should contact police on 101 or Crimestoppers anonymously on 0800 555111.