The 45-year-old manager of a restaurant in Essex was threatened with a handgun by masked robbers who then escaped with a large amount of money.
Two men entered an upstairs room of Mason's Restaurant, Ingrave Road, Brentwood, and forced the woman to hand over a four-figure sum of money.
Staff downstairs in the restaurant were unaware of the robbery until after the men had left.
The woman was uninjured but was left in a state of shock.
The robbers were described as white, possibly with Irish accents, and dressed in dark clothing and balaclavas.
Det Sgt Jamie Gingell said: "It is possible the men ran down an alleyway which leads to the East Ham housing estate and I want to hear from anyone who was in the immediate area near the restaurant, or within the estate who may have seen the men hanging around or saw where they went after the robbery."