Three men fled from a home in Berry Close, Oxford, after the owner challenged their claim that they were from the Inland Revenue.
Police have urged residents to be on their guard following the incident on Wednesday at 7.45pm.
The female occupier was upstairs when the doorbell rang. When she went downstairs she saw three males in the hallway who said they were from the Inland Revenue. The women went back upstairs to call her husband and the three men left.
Call 101 with information.