A man was hit in the face with a metal object before his attacker went through his pockets as he lay on the floor.
Police are appealing for information following the robbery which took place in Croyland Park, Wellingborough, on Thursday afternoon (August 23).
At some time between 2.30pm and 2.45pm, a 19-year-old man was walking in the park when he was approached by two men who were wearing hooded tops and put their hoods up.
A police spokesman said: “One of the men asked the victim what he had for him and then punched the man to his face with an unknown metal object he was carrying.
“The man fell to the floor and handed his attacker some money, hoping he would go away.
“The offender then went through the victim’s jacket pocket and stole more money, a Blackberry device and a packet of cigarettes.”
The two men then made off.
The second man watched as the attack took place.
The first offender was a man of mixed race, aged about 19, 5ft 8in, of medium build and with short curly black hair. He wore a black jacket, blue jeans and a white top.
The second offender was also of mixed race and aged about 19, 6ft and of skinny build. He wore a black jacket, black-and-white Adidas trousers, white trainers and a white baseball cap with the letters ‘NY’ in black on the front.
Witnesses to this incident, or anyone with information about it, can call Northamptonshire Police on 101 or information can be given anonymously to Crimestoppers on 0800 555111.