A burglar pinched a purse from a member of staff in a shop in Dunstable Road on Saturday.
The thief entered the shop between 11.30am and 12.30pm and found a door to the staff room at the rear of the shop had been left unlocked.
A purse was taken from a handbag in the staff room.
The offender is described as a black male, 5 ft 11 with a thin build and short black hair.
Beds Police are reminding staff to be vigilant and avoid leaving personal property behind counters.
Doors to flats, offices, and store rooms should be kept closed and locked at all times.
Be aware of groups of visitors that may try to distract staff away from the counter and till area.
Avoid keeping large amounts of cash either in the till, or in the office.
Consider fitting security lighting, CCTV and alarms.