Masked raiders stole a car when they struck at a shop in Wolverhampton in a raid which could be linked to others across the region.
Three people with their faces covered entered Ashmore Park One Stop in a dawn raid.
They stole a black BMW 335 – which belonged to a staff member – as well as cash and cigarettes.
Two staff members were in at the time of the raid, which happened at 6am, and were threatened by the three raiders, who had their faces covered.
Detective Sergeant Paul Reeves, from West Midlands Police is leading the investigation.
He said: “The investigation is in its very early stages but a number of witnesses have been spoken to and forensic scene investigators also scoured the store for clues.”
Last month terrified shopworkers were shut in a storeroom when robbers struck at Co-op in Wolverhampton Road, Penkridge.
The Ashmore Park incident is the latest in a string of raids, with others taking place in Bilbrook and Wombourne recently.