A man was out walking in Northampton when he was approached by three unknown males who demanded his wallet and then assaulted him.
The victim was struck with an 'unknown weapon' and also hit on the head in Mill Lane near Dallington Gym, Northamptonshire Police says.
A phone and tobacco was taken from the victim who needed hospital treatment for head injuries.
Officers are appealing for potential dashcam footage to help them find two offenders who assaulted the victim.
The offenders were all white, aged in their late teens, and they all wore face coverings.
Anyone with information about the incident which happened between 3.30am and 4.15am on Sunday, March 12, should call Northamptonshire Police on 101 or Crimestoppers, in confidence, on 0800 555111