A man suffered serious facial injuries after being assaulted in Kettering town centre.
The assault happened between 5.10pm and 5.30pm on Tuesday in Gold Street.
The victim, a 27-year-old man, was walking through the town centre when he was verbally abused by a man.
The man then punched the victim in the face causing him to fall, before running off.
The offender is described as white, about 5ft 10in to 5ft 11in, muscular and aged in his late 20s to early 30s.
He had short blonde hair and wore a dark T-shire and trousers. He had tattoos on both arms.
Witnesses, or anyone with any information, is asked to call Northamptonshire Police on 101 or Crimestoppers anonymously on 0800 555111 or use the anonymous online form at www.crimestoppers-uk.org.