Thames Valley Police is appealing for witnesses after a robbery on Monday morning.
At around 10.25am the victim, a 24-year-old man, was walking on the pedestrian bridge heading away from Milton Keynes Central library towards Coltsfoot Place, Conniburrow.
He was approached by three men, one black and two white. They spoke to him and when he did not reply, one of the white men restrained him while the black man stole cash from his pockets; all three of them then ran off towards Bradwell Common.
The offender who stole the cash is described as black, in his mid-20s, 5ft 9ins tall and of a medium, athletic build. He had a full beard, pierced ears with no earrings, and short hair. He was wearing a plain black hooded top and Adidas tracksuit bottoms and trainers. He had a tattoo on his left forearm.
The second offender was white, in his mid-20s, 6ft to 6ft 2ins and of medium to heavy build. He had cropped brown hair and was clean shaven. He was wearing a tracksuit top which was purple with a black and grey pattern, grey Nike trousers and white Nike air trainers.
The third offender was white, mid-20s and of tall, slim build. He had long wavy brown hair, was clean shaven and had DAD tattooed on his knuckles. He was wearing grey matching Lonsdale top and bottoms and tanned Timberland shoes.
Witnesses can call police on 101 or Crimestoppers, anonymously, on 0800 555 111.