Police are appealing for witnesses after a 13-year-old boy was punched and robbed while at Cineworld in the Xscape.
The incident happened at approximately 16:20 on Friday 13th August when the victim was buying tickets.
The 13-year-old boy was approached by a man and a woman. The man punched the victim in the face and stole his mobile phone.
The victim sustained bruising and reddening to his face but did not require hospital treatment.
The offender is described as a large white man, aged between 16 and 20 years-old. He was wearing a tracksuit and carrying a bag across his body.
Investigating officer Detective Constable Siobhan Jones, based at Milton Keynes police station, said: “I am appealing to anyone who may have seen this incident, or who may have information about what happened to please come forward.
“I am particularly keen to speak to the member of the public who helped the victim by standing in between them and the offender to come forward.
“If this was you or you have information, please contact police by calling 101 or making a report online, quoting reference 43210362990.
“Alternatively, if you wish to remain anonymous, you can contact the independent charity Crimestoppers on 0800 555 111 or via their website.”