A teenage boy had his phone stolen as he walked home from a house party in Westcroft.
He was sat on a bench in Westcroft Playing Field with a friend after leaving the party when three men approached them from Stourhead Gate around 11.30pm on Friday.
They demanded the boys phone and hit him on the forehead, before stealing his bag and Samsung Galaxy S3 mobile phone.
The victim suffered slight bruising to his face but did not need to go to hospital.
The first man is white, around 20-years-old, 5ft 10ins and of a large build wearing a white vest.
The second is white, around 16-years-old wearing a black tracksuit.
The third is also white and around 16-years-old but he was wearing black jeans.
DC Samantha Reynolds from Milton Keynes police station said: “The victim saw a woman walking a dog just prior to the robbery. We would like to identify this female to eliminate her from our enquiries.”
Any witnesses can call police on 101, or Crimestoppers, anonymously, on 0800 555 111.