Detectives in Cambridge are linking three street robberies committed by four men in less than an hour.
A man was punched and had his wallet and gold necklace stolen outside Barclays Bank, Market Hill, at about 0200 GMT on Wednesday.
About 10 minutes later, four men stole a man's bicycle near the junction of Queen's Road and Garret Hostel Lane.
Then at 0240 GMT two other people were attacked and one of them had his wallet stolen in Parker's Piece.
The four men were in their late teens to early 20s.
One was wearing a grey hooded top and black tracksuit bottoms, while another was white, with a shaved head.
Det Sgt Geoff Knight, of Cambridgeshire Police, said: "These street robberies were all carried out by a group of four men in a very short space of time.
"They all involved an element of violence and threats, and the victims have been left shaken up."