Officers have released CCTV of the moment two men carried out an armed robbery in Longstanton last week.
At about 10.20pm last Thursday (1 November) the pair entered a post office in High Street armed with a sledgehammer and knife, threatening two shop workers.
The pair left empty-handed and fled in the direction of Thornhill Place when a panic alarm was activated.
Ten minutes later, a shop in Church Street, Willingham, was robbed by two armed men. The pair made off with more than £800, cigarettes and a bottle of Lucozade.
DC Alex Dopadlik said: “This was extremely distressing for those working at the time.
“We believe the incidents are linked and we would urge anybody who saw those pictured at the time to get in touch.”
Anyone who recognises the men or has any information regarding the incidents should call police on 101 quoting incidents 463 of 1 November or contact Crimestoppers, anonymously, on 0800 555111 or via www.crimestoppers-uk.org.